Enshitification does not mean it becomes unpopular. It means it becomes non-valuable. If Instagram disappeared tomorrow, there are other platforms that will happily absorb those users because nothing important happens there anymore. Facebook is much the same; the only reason to engage on FB these days is because you are trying to do some kind of locals thing or neighborhood association nonsense.

I recommend you read the essay for enshitification, because I think you're mistaken my use of the word for a random pejorative instead of a description of a process that platforms go through in which they become bad for their users.

Reddit, maybe, will have a longterm position as "a place you go to for product reviews". Unless most people do the right thing and nuke their posting history. But it's gone down the enshitification road where it intentionally squanders its value for profit.