At heart, I agree with you and Smokey that GL is pretty well supported. But I'd like to see some evidence of its acceptance in the real-world marketplace.
Knights of the Old Republic. Requires an OpenGL 1.4 capable graphics card. I've read what can go wrong when game creators use cutting-edge hardware and forget that their intended players don't.
Well poor marketing is always a serious concern for any game creators, especially since most aren't too good at it. However I fail to see how this is effected by hardware requirements? There is no real reason to target Shader 3 min requirement anyway as there is a significant amount of Users with ATI 9600+ or X600+ which are both non Shader 3.
Rubbish. There are plenty of good reasons to make SM3.0 a minimum requirement (like dynamic lighting).