I can make a new website with a forum if Reddit goes "bad," too, but that doesn't change anything. All of the content and the users would be on that one specific instance. That's what people care about: content and a critical mass of users. There's a reason people are still using Reddit, and it's not because Reddit has wonderful ownership that cares about the users; it's because that's where the most people currently are. Migrating people from one site to another isn't easy, and that would be the exact same situation if a super popular instance were to go "bad," whether or not it's part of the Fediverse.