Part of the problem is expectation management.
What do you want users to expect from the service?
In my mind “syncing” happens in the here and now. I wouldn’t expect to have 1 year worth of version history for a sync service. In the words of the oficial help pages: “Syncing is not a backup”. I wouldn’t mind some history to recover from sync errors, but that could be automatically capped by time (“24 hours”) or storage (“5 GB”).
I wrote a feature request for an alternative scenario, where people would pay explicitly for the version history: Paid backup service - #8 by harr The primary expectation would not be the sync service, but a backup service.
The current situation is unsatisfactory, because users can’t do what they pay for (syncing), when the storage is blocked by an intransparent feature that is officially not supported (backup).