Microsoft has a real problem with DirectX 10. The problem is that the core audience for DirectX 10, gamers, are not upgrading to Microsoft Windows Vista. Since DirectX 10 only works on Vista, games with all the DirectX 10 goodies are not being played, or bought. Gabe Newell, President of Valve (makers of Half-Life, Half-Life 2, and the upcoming Orange Box) discussed this with Heise:
According to an online survey by Valve Software, only one in fifty players who access download service Steam has a DirectX 10-compatible graphics card and Windows Vista installed. In an interview with heise online, Gabe Newell, president of Valve Software, said that Microsoft made a terrible mistake releasing DirectX 10 for Vista only and excluding Windows XP. He said this decision affected the whole industry as so far only a very small percentage of players can use DirectX 10.
I think it is time for Microsoft to backport DirectX 10 to Windows XP. I feel bad for all my friends in the gaming development world. They want to use DirectX 10 to do some neat stuff, but it is not worth the loss in sales to put too much time and effort there. Fancy Shader Model 4.0 stuff is great eye-candy, but not at the expense of games selling and developers earning a living.