That is because everyone knows that ASICs are the inevitable end game. Whoever has those wins.
Even a ASICs design will have a hard time vs a few million gamers worldwide who consider their graphics cards free and GPU shrinks that happen every 18-24 months on average. Any ASIC design brought out today will have to compete with the radeon 7xxx series and not current hardware.
The point of the ASIC's is lower consumption. How can a 7XXX compete with a device that consumes 10 times less energy for the same bitcoins? ASIC's will make GPU mining obsolete.