I believe that it's only part of it. Another part is the lack of a filesystem. Many, if not most users, just don't like it or understand it. Though there are functions that are seriously lacking in iOS, I can't help but think that they're much closer to what is needed than MS.

It's only part of it but the primary reason.

The actual removal of abstraction (mouse) have made it much easier to use it. This is why my son at 2 can use the ipad and he can't use the mouse and keyboard for the desktop and laptops.

I agree but what would happen if your son had to navigate Windows Explorer on a touchscreen? He may never have to but if older users are experiencing similar difficulties with the filesystem, little can be done with the command bar to completely fix this issue.

I have no doubt that this UI, though cluttered, will help users out but I question whether this is ultimately the best solution.