Some of the greatest questions on StackOverflow are open ended like that.
I've gotten people to reverse closures before. They closed a Q&A pair I made on the finance site where I explained how I did something specific with the ledger software. Closed, then reopened with a positive score.
Not this time, I guess. I linked that question as an example but it didn't really convince anyone. I was frustrated but eventually I just accepted it, left it alone and went away for a few days.
Came back later to find they had just deleted the question along with the one answer I managed to write. That made me feel like shit. Certainly didn't expect that, especially not from a stack exchange site that's still in beta and thus in need of content.
That's actually a good example of why it happened, and may well be referenced in the meta threads when they talked about it - not only is there no correct answer, these usually acted like clickbait, farming for reputation to gain access to moderation tools.
There is no single correct answer. The answers posted can all be correct and they'll certainly help the people who ask these perennial questions since the question will show up on search results.
> these usually acted like clickbait, farming for reputation to gain access to moderation tools.
The reputation problem is solved by turning it into a community wiki so that votes won't be counted towards reputation. At least it used to be solved that way. Do those still exist? I wrote the posts on mobile and didn't see the usual "turn this into a community wiki" checkbox. I assumed they got rid of it. They've gotten rid of a lot of things over the years, I didn't really keep track.
Nothing you said explains why the post was deleted. They could've closed and locked it to prevent additional answers and voting if it's so problematic. They went the extra mile and completely trashed the answer I wrote. They trashed the efforts of other people who wrote helpful comments with references to additional papers on optimizations. Those comments taught me new stuff. They just deleted all of it. I discovered they had deleted the question because I tried to find those references and couldn't.
I can handle closures, downvotes, rude comments, even insults. Wikipedia style deletionism though? Yeah, that makes me think twice before posting anything there.
Plural? Obviously that wouldn't be accepted. It should be something that can have a single best answer.
Open-ended that allows an expert to expand and explain doesn't mean free-for-all.