That was my experience. I used (and not gently) hundreds of 5.25" floppies in the mid to late 1980s and had very few problems. Wore out drives, but the disks lasted forever. At first 3.25" disks were very good as well; it was normal to install a commercial software product that was distributed on a half dozen or more 3.25" disks that would all work perfectly year after year. Later quality dropped off and floppy media became rather unreliable.
I can only imagine how reliable a mil spec 8" drive with mil spec media must be.
The 5.25" disks were much more reliable than the 3.5". I had plenty of bad 3.5" after I used it a lot, but almost no bad 5.25" disk. Not sure if it was related to the areal density, rotational speed, head distance - I've seen scratched 3.5" disks quite often.
I still have a 8" disk in my desk's drawer, but I have no reader to check it. It is probably still good more than 25 years after the last time it was written (I have it since ~ 1992).
