Because the thing cost as much as most gaming systems. The price tag is about $1300. Do you really want or need a keyboard that cost about as much as you PC?
Not to mention their extremely limited in stock and quantities, and cost a arm and a leg to buy like mplich said.
Unless you want to have the biggest E-Peen ever on these forums, then go order one. I've only seen em so far on frozencpu.com and you have to call to order one. Not to mention they wont ship you one until the end of this year.