Because the only people that will buy/need a card like that can write the purchase off a business expense. That card is for graphical workstations. Like CGI/MAYA/3D Studio Max... (Hollywood)...Art Studios... Advertising... ETC...
Actually I know Quadro owners who apparently have no problems with using their cards to run games on, just as well as their desktop counterparts; the Quadro FX in question is based off the NV40/GeForce 6 series GPU.