It's in their best interest, too, like for WP7 or Windows 8 for ARM. Otherwise, both WP7 and Windows ARM for tablets will be less appealing for consumers because they won't have enough apps.
Unless, of course, the whole Windows on ARM thing is just vaporware to show customers "look - you don't have to switch away from Windows when you switch to ARM" hopping this delays customers looking into alternatives in the x86 space.
