I can't wait until they start introducing the start menu back in Windows 8.2.
Start Menu is overrated.
But with new Windows 8.1 and Windows 9 coming up, I don't see why they'd make DX12 Win7 compatible. Win8 already has a desktop mode. Win9 most likely will have the same. And seeing as MS wants people off of NT/2000 architecture and onto WinRT, it just makes more sense to have all the newest, shiny things for Win8 and above.
But I could be wrong and I'd be ok with that.
If Microsoft really wants to go through with pushing people off of NT and onto WinRT what they will accomplish is pushing people to Linux.
Personally, I don't see Win8 being so bad that it'll push people toward using Linux. I mean... it would have to be pretty bad. Mac OSX, maybe. But very doubtful. Mind you when I said WinRT, I didn't mean the Metro-only version. I meant the platform as a whole (Metro and Desktop).
But yeah, Win8 isn't so bad that if people were forced to use it, then suddenly would mass-abandon MS. I think that's hoping for too much.