I agree with most of that, but there are loads of embedded systems still running the equivalent of Windows XP and they’re chugging along just fine. That OS still receives updates and ending that would break a lot of backend stuff. Mostly banking.

Boeing just started making planes which don’t rely on floppy disks for updates. That will continue on the older part of the fleet until it’s no longer feasible to procure the disks or the planes are no longer airworthy. I mean, why not? If you only need to store a few mbs for something critical, it’s not a bad choice of medium.

If a system is secure, reliable and works for decades without complaint, there’s no need to fix that.