And... how many people, need that? To store 12 TB nightly? Few thousand businesses, perhaps? Not even your super-geekiest nerd is storing 1,800 tapes a year.
Well, of course - Pretty much nobody needs this for home use. But you're forgetting that, beyond those several thousand businesses, there's also the government. We have to back up nightly and retain stuff for a VERY long time. And the government, in case you haven't noticed, is big. And we have to back up everything, even if it's completely redundant it has to be a complete snap-shot. We use tape here because, for our needs, it makes practical and financial sense. I realize that most people don't associate government with being practical or financially responsible, but every once in a while there's a sensible nerd who can make a pretty chart with colorful lines representing $$ spent that's able to persuade the powers that be.
Tape's not dead, it just has limited situations where it makes sense. Home is rarely one of them.