One huge gain Apple made when switching to Intel in 2006 was the ability to natively run Windows. While Apple certainly made fun of the Microsoft operating system (like in the ad above), the ability to run OS X and Windows side-by-side is a huge selling point for power users.
For example, I use modern.IE virtual machines to QA websites at work. If I were to be running an ARM-based Mac, I wouldn't be able to do this. As much as Apple might like to think its customers can be OS X-only, I'm not alone in these needs.
Stephen's 100% right. I know plenty of people in the enterprise and education who still use VMware for that 1 app they need to use that is Windows only.