Once Windows supports the right hardware, it should be easy to boot Windows on a Mac. I don't think Apple is worried about that. OTOH, VM software is getting pretty good, and there's no architecture-translation performance penalty for the Intel Macs.
The problem is with software development. Why go to the expense of dual development if you can switch to Windows while running a Mac?
I run Windows programs on my G4 Mac now - with MSFT's blessing. Its a bit slow but it works and with Intel Macs it will be the same technology but with a native (vs emulation) instruction set.