Hardly. The Fediverse spans multiple apps and services, and it existed before Elon bought Twitter and it will continue existing regardless of what the billionaires do, because it’s not run by just one person.
The whole point is decentralization, not growth, so unless the billionaires can take out every server hosting an instance, the Fediverse isn’t going anywhere.
I know I can’t ever go back. I donate to my instance, and I actually feel good about it, because I know it’s not going into the pocket of some faceless corporation who’s beholden to its shareholders instead of its customers.