Vista is hardly adapting to new technology... It's just another operating system with some fancy bells and whistles. As a matter of fact, it's nothing that hasn't been done before and there really is nothing "new" about it.
DX10 could well have gone onto Windows XP, but they would have had to re-write the way XP handles drivers
[I actually read that on a Microsoft blog]. They would rather force people onto Vista and make profit. Fair enough, yeah? Well no, not for a company who has such a dominant market position. When a company has such near-monopoly, they should have to act much differently to an every day company with real competition.
There are other people working on DX10 alternatives, and these people are very intelligent programmers who very likely know more than anyone on these forums about operating systems and DX10. So don't go saying "DX10 on XP is impossible"

I know theres the people working on ReactOS who are making a complete DX10 implementation, albeit on their own OS but that's based on Windows NT/XP's structure. There's also people from Wine who are "warping" DX10 commands to OpenGL commands, and people at FallingLeft (alky) who are working on converting .exe's to multiple OS formats (primarily from windows to mac) using their "alkinator".
I rekon DX10 is Vista-only
mainly because MS want you all on a new operating system to make them lots of money. Of course it wouldn't work out great for them if they made a Windows XP patch which completely re-wrote the way drivers work, but it's not like Microsoft don't have the funds is it.
PS3 games have good reason not to work on a PS2 - the PS2 has old hardware, it's not like different software on a PS2 would make PS3 games work.
Anyway I think you get the jist of my opinion here

I'm not spending £100 on upgrading to Vista. If I felt like I were doing so out of my own free choice then yeah, maybe I would... but I'm just like that - if someone tries to force me to do something, I'll try as hard as I can to not do it (generally speaking) especially when my own money is involved!
I could moan about this forever bringing up random annoyances of mine... but I'll spare you from it
Jerrys Final Words: Microsoft need to stop trying to create captive markets, and start interoperating and creating open standards in the interest of the consumer. Big companies have big responsibilities.