You'd be surprised.
I have a RL friend who's on Reddit all the time, and he didn't even hear about the shutdown, much less /r/place, or anything like lemmy. I've been trying to sell it to him...
Re: The "We're elite" becomes "We're bored talking among the same old people" or "We're burned out", leading to users leaving and formerly thriving communities dying.
I've been around long enough to see this happen on multiple forums.
Featured in anime series Yuru Camp Season 3, episodes 3 and 4.