The guy who told you it was five or so years ago was probably me, and I was wrong.
It wasn't malicious, it was just one guy sick of juggling cartridges and looking for a better way of doing things.
While I find tape hopeless for any kind of operational backup & recovery it's perfectly acceptable for deep archival. It doesn't use any power when it sits on shelf and if you're a backup bod hopefully it becomes someone elses problem after you've sent it off to the vault. With any luck when the time comes to go digging through tapes looking for the seven or eight year old cartridges someone has requested you'll have a higher paying job doing something else and it'll become someone else's problem to figure out what's required to get the data off those cartridge.
Would I like to have to perform a DR restore from tape or recover a huge saveset if I've been multiplexing my backups? I've done that, and if I want an excuse to go on holiday very few excuses are better than "It's restoring from tape." That's usually followed by "Just keep feeding the autochanger I'll be back in two weeks."
Tape is dull & boring as a technology and can be painful to manage in the backup strategy. But we all know that. We all know how it works. We know where not to use it. And we know how to get the job done with it.
The end result is that it's not going anywhere for a long time yet. Or at least it isn't until we have a fresh crop of Backup Admins who've never had to back anything up to tape or restore anything from tape.