MS is, as usual, lying about DX10 not being easy to port to Vista. The fact is, other than GPU task switching and some memory features, DX10 shaders could indeed be ported to XP without many changes. It is the hardware and drivers that are doing the work; DX10 is a way to communicate with them.
What it comes down to is whether or not gamers care about GPU task switching (multiple 3D apps vs. 1) and if a unified memory pool really matters for near-future games, or whether it could all be done on XP.
DX10 hardware works in Macs and Linux as well, maybe someone should ask Microsoft how that is possible considering their claims that only Vista can take advantage of the new features.
"...new customers." is right.
This comment was edited on Feb 16, 00:58.