But go pull the post-close EOY General Journal from 1996 off of one, I dare you.
I've got school stuff older than that, copied from one generation of drives to the next since the 1980s without ever needing a tape drive. Most data is lost because there's not enough redundancy and integrity checking, a private backup cloud makes total sense to me just add another node and it'll sync up another perfect copy. Doesn't matter what the underlying hardware is, as long as there's enough of them and it gets replaced in a timely fashion. Assuming that takes care of physical and geographical redundancy, you're left with misconfiguration, internal or external malice.
True, it's possible to make deleting disk backups easy. It's also possible to make it almost as hard as deleting tape backups by using a third party, sign off procedures and such. The only time you gain a significant advantage with tape is if you got a human in the process as an air gap defense, if you got a tape robot - which is what you want for a large, automated system - then theoretically whoever could hack your disk backup server could just as easily hack your tape robot server and instruct it to wipe all the tapes. Unless you use WORM media, but I don't think many do unless they absolutely must for legal compliance since you can't recycle tapes.
Even if something is irreplaceable it doesn't mean it's of infinite worth. A one-way file transfer gateway to a backup server in a mountain bunker might be enough, even if it's stored on a R/W disk. At least it starts competing with other far out possibilities like the hacker /sysadmin disabling or encrypting your backups until one day you wake up to "Your data is locked, pay me $$$ or go fish" or worse "Thanks for laying me off here's the letters F and U" only to discover the backups are useless. And I don't mean just an occasional restore test, if you're that paranoid you should also verify that what's on your WORM drives is what you so desperately need bullet proof backup of.
Ultimately the more exotic a technology gets, the less find it worth it which can lead to a negative loop where the lesser technology wins out anyway. I don't think tape will die but it can become more specialized, like companies don't having their own tape drives they just send encrypted backups to companies specializing in disaster recovery for when everything else has been nuked and just run the risk that the day-to-day operations are well enough secured by disk backup. Losing a day's worth of work is expensive, but also not fatal to most businesses.