Mind you, communities/groups, obviously imitating subreddits, as well as the marketplace are saving it quite well from ending up like MySpace/Hi5. It's also evident that there has been a significant boomer infestation to the userbase the past 10 years.
The communities/groups are significantly higher quality than the average subreddit, especially for niche subjects.
Frankly they're the only thing I use Facebook for, because the people on hobby groups are way more knowledgeable than those on reddit and they largely don't tolerate meme posts.
yeah, 90% of what I use it for is my internal group from my work friends about who's taking what shift on my side job, and Volkswagen repair groups - which are an absolute gold mine of experience and info.