No, that will always be happening. The only thing that will settle is that the trusted instances will become known and people will stop signing up for less trusted ones.
That's the issue though. Without a locked identity on an instance, people will naturally choose the option they think is least likely to disappear in a few weeks.
Notice how everyone pretty much uses gmail? If gmail goes down you lose access to everything, but it won't because it's google and they have money to throw at problems. That's not true for Lemmy (and we don't want that because it leads to Reddit 2.0 where all power is centralized).
No, that will always be happening. The only thing that will settle is that the trusted instances will become known and people will stop signing up for less trusted ones.