I have the opposite experience, at least with regard to your first two paragraphs. Most of the things that I have backed up on other people's computers over the past 3-4 decades are irretrievably lost. But most of the things that I have taken care to make backups of on personal equipment over the years, are still with me.

Cloud storage is still useful of course, but I prefer to view it as a cache rather than as a dependable backup.