Greetings cyberjock!
I'm not so sure about that idea, but please allow me (purely academic discussion). Went to slashdot in search of the mentioned thread, and maybe its the one from "storagedude", which was a link to an article on enterprisestorageforum. Reading the articles I could not conclude that tape was dying anytime soon (as indeed mentioned by the original author).
Tape has (very) clear advantages over disk, mainly in data density, data longevity and reliability, not to mention total cost of ownership.
In the sake of full redundancy, backups must (or at the very least should) be stored on more than one media type. Unless there is some other high data density technology it's pretty much down to hard drives and tapes. Not to mention compliance with data archive agreements which in most cases forces tape to be used. Emphasis on the archive part.
Cloud is out of the questions for reasons which I think are not worth arguing here.
Just for context, Google implemented RAID4 over tape. Several reasonings for this, but a big one is precisely the fact that it isn't HDD. As mentioned by Raymond Blum they would use punch cards if they were efficient enough.
Joke aside, I also believe tape will be replaced by another technology some day, but unless I missed some big news in the area I have yet to see an alternative appear.
Please note that I am a huge fan of ZFS, but it has nothing to do with this discussion. ZFS is a file system, mainly running on top of magnetic disks. We are talking about media here, it's a different layer.
Cheers!