This should remind people of what they did with DirectX 10 and Windows XP. No technical justification; just another way to force people to pay for an OS upgrade, etc.. Sad times. -- Making life hard for others since 1977. I speak for myself and not my employer/affiliates of my employer.
Well, it's just a .1 difference anyways. Were not talking about a FULL version change here like 10.0 - 11.0. I don't see any reason why 11.1 couldn't be implemented in Windows 7.
Cost-benefit. 11.1's selling feature is native (DirectX) stereoscopic support. As DX9 is still far outnumbering DX11 applications, the cost to bring the new features to an OS that lacks the underlying support specifically written for the .1 updates for 0 real world applications was not deemed appropriate. Same will be true in 6 months when we are still sitting at 0 real world applications requiring 11.1. 11.1 was needed for Win 8's interface.