Why ?, I think you are confusing the traditional PC market with the iphone/itouch market. They are ENTIRELY different.
One assuming many many more women and younger children/teens (again many more female) play games on itouch/iphone than ever would on the PC platform. Angry birds is a much more "friendly", light game to play, and in those terms is much more accessible.
Not to mention that the game costs one dollar, has no control issues, allows progression on multiple levels, has loads of content, and is continually updated with more. And it's fun.
Furthermore it is designed for handhelds rather than adapted to the platform. The control issues that seems inherent in the second approach have ruined too many games for me - for instance, no more virtual joysticks please. If you don't have the real thing, come up with something better, not a cludgy simacrulum.
The handheld market holds the potential to rewrite the gaming landscape radically - what gets mainstream attention, which companies are dominant and/or creative and/or distinctive. JC makes interesting observations about creativity and how difficult it is to break the mold in the current gaming landscape. Change of the status quo is welcome IMHO, it's about time for disruption.