Sure, but here's the thing. If we all just moved to another centralized system, we'd just be setting the timer for the next heartbreak. It's a matter of when, not if.
Lemmy's growth will be slow. It may even stagnate. But, unlike Orkut, Friendster, Google+, etc. it can't be taken away from us. lemmy.ml might even shut down, but the Fediverse will always be here in one form or another.