Tapes aren't really archival, either, unless you have several copies. I've done batch recapture off of DV after a few years, and swore when I found serious dropouts. That's relatively low density data compared with LTO (though admittedly with less redundancy and error correction). After that, I dug around and found a copy of the captured files on some old hard drives, which unlike the tape, were intact.
So basically, from what I've seen, nothing is truly archival unless you have multiple copies, and if you have multiple copies, just about everything is archival, so the difference between tape and hard drives is that tape drives require a large up-front investment in a drive in exchange for cheaper per-TB costs for the media and higher physical density (because you don't have redundant electronics going along for the ride). If the per-TB costs aren't less and the density isn't higher, then tape offers no real advantage over spinning disks, IMO, unless your data storage needs are so massive that you have automatic libraries, and even then, only if you can't find a company willing to build a hard-disk-based librarian robot.