If you want the future of IP in whatever form protected, you need DRM. This of course changes the kernel. If SW companies dont want to spend the money to make their apps compatable, thats up to them.
Anything can run on Vista or W7, but if these SW companies wanna slack, it wont.
Just like the billion dollar gaming industry, how many DX10.1 games do you see out? Its easy to do. When DX11 comes, itll even be easier, as the DX9 model already exists, as well as the DX10 model in the DX10 games we already have. Its quite easy to add DX11, but how long, and how many will do so, when their current games are still being sold without a change?
To stick M$ with compatibility issues under this kind of business climate just isnt really looking into it deep enough, because its not Vista or W7 being unable to use these apps/games, its the devs and managers etc refusing to upgrade, and to accuse M$ or any of its OS' ever for this is wrong.
If your clientele is using a particular OS at a 80% rate, it wont be a motive to move to a different OS support, unless its certain clients you really need to keep, or, your just a good company keeping up with the times.
If, however youve boughten into the, "what have you done for us lately?" model of business practices, theyll hedge to upgrade til the very end. Again, not a OS problem, but a business problem.