I understand what you are saying, but that statement is not quite correct. From 7 to 8 we moved into a completely different world which is ruled now by tablets and phones. MS has to provide an interface that is suitable for those devices.Microsoft does not need to make these changes to the OS (it's called marketing).
The could have, of course, seperated the OS for the portable devices from the OS for PCs. But that is a very expensive proposition. Maintaining 2 seperate OS is extremely expensive if you want to keep them halfway in sync as far as the functions are concerned. I have been there and know that it is a nightmare.
Oh, and Xp is no longer supported so those still using it are taking a big risk with security issues. But hey.. that's their problems not mine. I would rather use Linux than Xp right now. I can agree that for the average user Win7 is just fine for now and for the next 5 years but keeping them on Xp is doing them a disservice. IMO
What ??? No seat belts, standing room only and 2 horsepower ?
OOP is really nothing new. We used it for mainframe programming in the 80s.