I feel like most will just stay but it will never feel the same. As for what could possibly replace it, at least for me, it has been a conglomoration of different things serving different purposes. Lemmy is good for seeing discussion, RSS for my own personal link aggregation, and then the occasional browsing of something like Mastodon which just hits a bit different personally. Those together have more or less quenched my desire for reddit for anything except hitting it on Google Search results.