Ironically floppies are utterly unreliable and will become corrupted if you look at them the wrong way. I understand that if you are after reliability you have incentives not to change, but it sounds weird to me that you wouldn't move away from that terrible format as soon as a better one like usb storage became available and prominent.
I have a 1987 Apple //c with a bunch of 5.25" floppies of the same period and they all work just fine : games, UCSD Pascal, utilities, Mouse Desk...
Not in my experience. Mine all failed.
Commercial optical disks, as in the disks that you got when you bought games and movies and the like, are physically stamped. The data is recorded as physical pits that are stamped onto the disk from a master copy. That disk isn't degrading unless it suffers severe external physical damage.
By contrast, recordable optical disks write their data using inks and dyes that are burned by a recording drive's laser. These inks and dyes can and will degrade over time, eventually leading to data loss.
The CD's (media) in those times were surely more durable, but also the actual drives were much more robust.
I still have somewhere a (SCSI) CDRW drive using one of those "caddies" that can read at 1x that could sometimes read old CD's that more modern drives failed at (used to, it's a lot of time I don't use it).
If you had equipment from say 1990 and blank disks from then too and a reason to keep it running, it likely still is. Although floppy disk emulators are probably a reasonable retrofit in most applications.
It ends up being that some manufacturers made good stuff and some made junk, but you don't know which until much later.
I have a batch of nos nameless 3.5" 720k I got from floppydisk.com that are basically all junk. Fail to even verify a format, or maybe succeeds once and then fails within 3 uses.
I have other even older, actually labelled as single sided 3.5", but made by Basf that just run and run and run.
In fact most 8" are even more reliable than any of the later versions because a lot of 8" machines spun the disks the entire time the machine was on. All day every day at work that disk is just grinding away... so they had to be good just to be usable at all.
I sent them to a guy who writes the emulator for that system and three out of four were totally readable.
This is probably fine for writing emulators, but it is not quite the reliability I expect from aviation!