[skeleton]

I formed the opinion that Facebook (the service) was in trouble back in 2014-2015 when I noticed the site appeared to becoming more about interaction with content posted by 'meme pages' and such rather than content produced by friends.

Facebook as a company will probably be fine as it has its tentacles in all sorts of places now.

[rhizome]

I think a lot of that has to do with the popularization of the meme (image macro) as a form of internet creativity. Facebook certainly was an outlet for that and they didn't impose much if anything to slow it down, but so was everywhere else you can post an image.