This seems to be a serious downside to this system. Anyone who values a persistent profile is putting their precious data in the hands of some random instance that may or may not go bust in the near or (perhaps worse) distant future.

Isn't this the downside to any system reliant on remote operators?

For any truly valuable data, the solutions remain the same, keep local copies, create backups, and store some backups offsite. As-is it seems like perhaps too many people rely strictly on offsite solutions as their singular data store, which is as bad practice as only having local backups, tbh.