There was one Voat. When the one Voat goes bust, Voat goes bust. Like any enterprise, it’s failure can be attributed, at least in part, to poor management.
There are many Lemmy’s. If one Lemmy collapses, another Lemmy can take its place. The individual instances might be less stable than a centralized social media site, like Voat was, but when federated the whole unit is more resilient than centralized social media.