But can't the same problem happen if you, somehow, lose the ownership of your domain? I mean, I don't know what the actual assurances are, but if there is any chance that you may lose access to your domain (for causes other than forgetting to pay to renew, ofc), even temporarily, that would be the same as being banned from Google. Or even worse, because having your Google account locked means you can't use it but noone can use it either; however, if somebody now has your domain, they could be able to impersonate you.

I think that is very very uncommon and when it does happen there's usually some kind of legal process involved. In other words I don't think you're going to have your domain yanked away without some reasonable amount of warning and ability to dispute.

In the worst case scenario you'd have time to setup a new domain and move everything over. Annoying yes, but again extraordinarily rare.