This question is my reason. Why are you able to post two answers instead of displaying all the alternatives in one answer?
If you have one answer which propose a lot of different solutions then that should be most helpful for future visitors.
I have answered things with two answers when the two answers are significantly different and essentially represent two completely different, incompatible approaches.
I've actually done this more than a few times. As have some other users. Here are a few of mine:
I hope those instances represent me well. They were randomly picked.
There is clearly a line when doing things like this is silly. There's no point in suggesting somebody
mv file /dev/null when they can just
rm file and that's certainly not worth another answer. The same would go for some answers which should probably just be comments "Have you tried x, y, z?"
The problem is you want us to say one thing is right or wrong but I don't think the line is clear enough to set a rule on what people can and can't do with regards to multiple answers. "Keep it sensible and logical" is about the best I can do.
It is reasonable to expect that there will be multiple answers provided by multiple people to any given question. More than one answer may be correct. The point of the site is that the best answers will float to the top as they accumulate more votes from the community. It is reasonable to expect that those asking questions will have to read multiple answers and decide what they want to do, or what to try first, and they can use the votes on an answer to help make this decision.
Note that although "best" is normally quite a vague term, here it means whatever the community decides is best, based on the number of votes.
To avoid confusion, from now I'll use "answer" to mean an answer as posted to the site, and "solution" as a separate item that can be thought of on its own. For example: in the question you linked, I wrote two solutions across two answers, whereas you said you'd prefer to see both solutions in a single answer.
If I can provide multiple independent solutions that have no connection to another, I don't necessarily know which the community will think is best. If I bundle them into a single answer and one of them is a good idea, the community may vote the whole answer up. But the community cannot highlight a particular solution, so people who read the page cannot determine which solution the community thought was best.
If multiple people answer, each with a bunch of solutions per answer, then the situation gets even more confusing. One of the solutions in an answer may be wrong and misleading, and another solution absolutely correct. So should the community vote it up or down? Why are we voting one set of solutions up, against another different set of solutions, when really the best solutions are mixed up across both sets?
It makes more sense to post one solution per answer, so that each can be voted on its own merits.
Otherwise, this becomes a very person-shaped view. You end up voting up the person, and not the answer. But the goal is to get a high quality set of questions and answers, and the community can even edit answers, when they have enough reputation. So it shouldn't matter who posted the answer. But bundling a set of solutions into a single answer ends up being one author per answer (potentially with multiple solutions each), since each author must necessarily post at least one answer.
This doesn't really make sense for multiple answers that are somehow related to one another. For example: I have presented multiple arguments in this answer, but am putting them together to present a single opinion. It makes sense to do this in a single answer, since my arguments should be considered together and not separately.
So I think it's best to use one answer per independent solution.