Here are the two top answers that I've written. They both have 8 upvotes. You'll notice they are relatively simple answers.
Now here are two of my own Q&As that I spent quite a bit of time working on, and one has 1 upvote, and the other has 0.
And here's a really nice answer by @SeverusTux: https://askubuntu.com/a/809656/518562
What is it about the two simple answers mentioned at the top that attract so many votes? Not that I'm complaining :)
Here's an analogy to think about: why more people like fast food, instead of specialized cuisine?
From the "customer" (question asker or visitor) point of view the same reason as fast food applies: people like answers that are quick to test , easy to copy-paste, easy to verify. Questions for which I write long scripting solutions don't always gain much attention - it would require user adding a script, playing around with settings to make it work, etc. Not a lot of people want to indulge into that.
From the point of view of other people who answer that question, relatively simple questions and simple solutions attract more attention. Often I will find myself answering a text processing or renaming question , and will be like "Yup, that guy's got a good way,too, and it's pretty simple ; why I didn't think of it myself ? Upvoted !"
Each question attracts specialized type of audience. You will see chili555 answering mainly networking question, me and Jacob Vlijm answering scripting questions that border on creating custom applications, A.B. ( who recently has not been active ) answering mostly package management questions, heemayl who answers bash and command line questions. The more specialized the question, the less likely people to view it and test an answer. From your example, question about the hardware clock ( which really should have been closed as off-topic, by the way ) is relatively easy to answer and most computer-savvy people know about the CMOS battery, so of course it will be attracting more traffic , hence higher likelihood of upvotes.
On the other hand, not a lot of people mess with bootloaders or have desire to go into that level of experimenting. Hardware-specific questions attract less audience,too. My personal response is often "Well, I don't have access to this same hardware - I am a broke college student who barely could afford this laptop, so how do you expect me to troubleshoot yours ?"
This is not too different form fast-food analogy. Many people can relate to burgers, but very few can relate to properly tasting wines and some unique steaks.
I've slightly touched on this already. Many people find a question and go "Yup, I would do the same". Especially if the answer is simple, short, can be even found in man page. With fast food analogy , I remember from economics class that there is a psychological factor to it - people like fast food not only for simplicity but because it's available in more places and will be exact same. Suppose you have a sys admin who spend years in managing Linux servers , sees a question and tries to answer, and then sees you posted something similar to what he would expect. There you go, there's a person who expected to find exactly the same thing, just not in their usual setting.
How many people will say " Yup, I would write this same script to automatically set up mouse or keyboard via polling dbus or xinput?" Again, very specialized audience is needed here, and high probability of "yup".
Quite the opposite: if you have a specialized type of tags and questions you like answering, by all means do answer them. It is likely that you will have much less competition and the community eventually will recognize that your answers are good. Occasionally, such questions may even have bounty on them.
Growing reputation isn't an immoral thing ( contrary to what some users may think ), so by all means do participate in those easy questions as well.
General and simple (sometimes even stupidly simple) questions that don't focus on a technical detail or problem which might be only relevant for few persons, but interesting for many users attract the most views and therefore have the highest potential to accumulate votes on both the question and its answers. Another advantage of simple questions and answers is that more users know whether your answer is right or wrong without thinking much, which makes voting more easy. Seeing a question which they might be able to answer themselves also increases the chance they view it and vote on existing answers.
The real-time clock question would be an example for this. It's stupidly simple and although I would argue that it's off-topic (hardware, not Ubuntu), but many people might be curious about this, look at it and vote.
On the other hand, very specific problems, even if you put much effort in solving them, are only relevant to a small circle of people. They are not that interesting to the wider audience and get less views and less votes.
Of course they must be correct and useful, but to attract votes they should also be well formatted (paragraphs, headlines, bullet points, separator lines, code blocks, block quotes, bold/italic highlighting, ...) so that the important content can be identified at the first glance.
Pictures and screenshots that help visualizing what you say are also a great vote bait if they fit. Adding references and links for further reading is a good thing as well.
The traffic that the question receives
There is a huge difference in the amount of traffic a question receives. A common question or one that ranks well on Google can get thousands of times as much traffic as another question. This is the reason you can go into some questions which have top answers with over 300 upvotes, and others where the top answers have 1 or 2 upvotes.
How highly ranked the answer is already
Assuming there is a high-traffic question with many answers, the answers that appear at the top gain more upvotes at a much higher rate. This means that a "good enough" answer that gets in early and gains some upvotes at an early stage can be advantaged over later answers once traffic starts increasing to the question.
That said, the nature of the audience here means that a small but significant number of people do spend effort reading the other answers, so an answer that is significantly better still has a chance of rising to the top (or near top, if there's an accepted answer already).
How authoritative the answer feels
This is hard to quantify, but answers that confidently make statements in a matter-of-fact way, and appear to correctly use technical terminology give off the impression of being written by an "expert" and tend to do better.
Simplicity of language
Shorter answers are not necessarily advantaged, in fact often the most-upvoted answers are quite long. The difference is that they use language that is easy to understand.
Good formatting
Good layout of an answer, including subheadings, correct formatting for code samples, bolding important points and appropriate separation of text into paragraphs have an advantage. In the case of two answers that essentially say the same thing, though written independently of each other, the one with better formatting and a heading (or multiple headings) often does better.
Whether the answer is self-contained
Answers which direct the reader to a different website don't tend to do as well. This is not just because the site policy which discourages answers which are only links, but also because they direct the reader away from this website, and therefore less likely to come back to the page that has the answer on it in order to upvote.
Echoing the above, but I'd like to propose another potential indicator: both of the lower-voted answers you've referenced are ones where you answered your own question, with little to no input contributed by other users.
Not that self-confirmed answers are inherently less useful, but when you compare that to a lack of varied answers (or comments) from other users, and an average or low view count, the signs add up to indicate a question (and thus answer) that is of relatively less interest to the community at large. (As others have already pointed out.)
For myself personally, I know that that the majority of questions I encounter (and wind up upvoting) on SE communities are ones I find via Google when I'm trying to find a solution to a similar (or the same) problem. I also tend to pay more attention to the answers on questions I've answered myself, to see how they compare and what the discourse looks like (so the wider the spread of answers, the more likely I am to scan/upvote).
If you suspect that the issue in question is more commonly experienced than the votes indicate, it could be that you're just phrasing it in a way that makes it hard to find. You could try writing the question with SEO-minded wording to see if that garners it more attention on Google or in the community search results.
Search engines will typically pay the most attention to an SE community question than an answer (since the question composes the meta title, main heading, and slug of the page), so the more likely the question is to appear in search results, the more likely people are to read/vote your answer as well.
I'm guilty of up-voting your Real Time Clock answer a week ago. I thought the picture of the RTC was hilarious. I could up-vote your USB problem because I suffered something similar using dd to create bootable USB from .ISO file last month.
I think popular up-votes are from common questions everyone has. When I first started working with PC's the current date and time was the first thing you were prompted for and replacing clock watch batteries on the motherboard was common practice.
I didn't up-vote your USB answer (I just read) because I can't remember if I had the exact same problem you had... it was very similar but not a guarantee. Experimenting with the USB again and recreating the problem is not worth the effort of authenticating an up-vote to you from me.
FTR, I think even the most humble appreciate up-votes. However, I want to avoid writing answers tailored to garner votes. I simply want to write honestly, from the heart and using my writing style that is not sexed up in any way. If you can't be yourself on the internet then all those freedoms lost in the real world (due to Big Brother, SJW's, PC or whatever) are now lost digitally too.
HTH.
