Uhh, stop trying to bash me, you know what I ment.
At least 3 years at the VERY LEAST untill it will be used as DX9 is being used nowdays.
And even then, as far as I know, any ati x800 [and above] and nvidia 6600/gt [and above] will get a patch at some point to support DX10... remember its NOT A HARDWARE! JUST A PROGRAM!! hardware CAN be adjusted to work with a certain program, if a patch is released and I believe it will be not much after the release of the DX10 for the 'native' DX 10 cards.