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".
Does it mean posting complex answers won't help you grow reputation?
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.