Yeah, a big fear of mine is having ten years worth of photos deleted in one fell swoop (or, at least, access to them removed without recourse, which comes to the same thing) because an AI thinks that a half-nude photo of my three-year-old is CSAM.
Of course, what that actually means in practice is that I should just regularly archive.
I think making sure to have a backup of your important content is always necessary. Being able yo conventiently port to another service, less so. I'm less concerend about the real risks of me flagged as some deviant, as long as I can pick up my data and give two fingers to the company that behaves in an unreasonably poor manner, im good.
realistically, our wifes and family will almost never make backups, and probably most of us hackers either, it ll stay on todo or as implemented but now broken script.
Of course, what that actually means in practice is that I should just regularly archive.