Why do good floppy disks go bad?

[Tom Gardner]

As a number of folks have pointed out it's not the magnetic particles - rust
is pretty stable; they read a 60 year old RAMAC at the CHM every week or so.

And it's not likely the binder, fully cured epoxies are also very stable.
Note disks do not have the tension problem that tape has.

And it's not likely the substrate, again Mylar is very stable

My guess it is both contamination and wear of the head.  After all, this is
contact recording.

Tom