Tech nightmares that keep Turing Award winners up at night

The existence of emulators is a big mitigator in software disappearing. As long as each generation of computers can emulate the architecture of the previous generation, there's a chain that can read any file format. Heck, my web browser can emulate Kid Pix and read its file format: https://jamesfriend.com.au/pce-js/. And speed isn't an issue since parallelizing file conversion on billions of files is trivial in the cloud.

Now, _data_ integrity being dependent on the continued existence of a single corporate entity is another issue altogether. But as long as your bytes are backed up personally on the latest generation of physical media, the bytes of the software you use to access them are backed up personally, you have a specification of the hardware architecture needed to run that software, and you have a chain of emulators that reach back to that architecture, then you're fine.

I have to point out that most image formats are actually rather simple. I very much doubt a competent engineer could not reverse engineer the formats in a week.