Why can't it be an ultrabook requirement to have a clean copy of Windows?

Ultrabooks power and style are ruined by ugly third party programs advertising and bad desktop management. Only 2 ultrabooks come with clean operating systems, the MacBook Air, because all apple products come with clean installs of their operating systems. The other one is the the vizio tin+light which had what was called "Genuine Windows" which just had windows and the drivers, nothing else, too bad the hardware on the laptop was bad and it got terrible reviews. The next round of ultrabooks should have 2 things 802.11ac wi-fi and a clean copy of windows 8 64-bit