I think it is gonna crash and burn without any survivors, but I'd say "the site keeps trucking along but is shittier and stagnant like Reddit" is more likely than "dies and everyone leaves to the next big thing".

Facebook/Twitter/Reddit/etc are the most popular versions of their respective form of social media, and if they do turn a profit, it's through arcane financial bullshit or based on cooked numbers. Forums never came back after reddit/discord, every attempt at creating another reddit has been a failure that's been unable to attract a sizable audience and would have been closer to achieving their goals if they didn't use this godawful format (see: this site). Combined with a crumbling internet infrastructure and declining living standards, the only way I see these platforms surviving the decade would be if the US government saw enough value in the social control that social media provides (which might be the case, there's a reason reddit's ran top to bottom by glowies) to where they'd dump cash in these companies to keep them afloat.