I don't think that's true.
I was at Microsoft when they user-tested Windows 7 to death. Including installing eye tracking software during sessions so you could monitor where the user was looking at on the screen.
That data was in part used to justify the changes made in 8: "Users only click on the start menu 0.1% of the time and when they do they focus on a narrow portion of the screen."
how do you go from
> the users don't focus on this menu much
to
> therefore we need to make this menu as large as possible
shouldn't the conclusion have been "the start menu is so great the user doesn't even need to focus on using it". it feels like desperately trying to make the data fit the predefined conclusion, despite the data screaming and kicking.
A couple of the UX people who worked on Win8 told me that some of the UX study results were faked to give the desired results that justified the new Win8 design changes.
Def the sort of stories you hear at at a bar after work.