Hmm, so what about these modern high density hard drives which store track parameters for their servos in on-board flash (aka OptiNAND)? Do we get "spinning rust" which might loose the information where exactly it stored the data?
OptiNAND is a "SSHD" and thus has the same concerns with retention as an SSD. https://en.wikipedia.org/wiki/Hybrid_drive
the real issue here is QLC in which the flash cell's margins are being squeezed enthusiastically...