I don't think Microsoft cares that much about ARM one way or the other but it is clear that Microsoft's big push in that effort is going to hurt ARM. Window RT is not working out very well for them and has left consumers a bit confused. Intel will fix all this for them by releasing an x86 chip that will work with a regular WIndows OS and be power thrifty.
This year is kind of the tipping point for ARM in my estimation. Intel is getting to the point where they have competitive chips for mobile devices and on the other hand the needs of smart phones are sort of outgrowing ARM which really never evisioned this much performance being needed by a phone.
I am heavily long both MSFT and INTC. I really think folks are badly underestimating both companies and their push toward mobile. Obviously they underestimated the growth in smart handsets but make no mistake they are able competitors. MSFT virtually destroyed AAPL on the desktop and INTC virtually destroyed AMD in the CPU market. One thing I know about both companies is that they may not get it exactly right out of the box but they are relentless.
Get ready for the rise of Wintel in the mobile space.
Microsoft doesn't have enough collective intelligence to do anything that clever, but you're right on the outcome. Consumers haven't really been aware what processor was in their smartphone because the vendors promote their own flavor of ARM's design. So Windows RT is the public's first recognition of ARM because they had to learn about it when they discovered ARM doesn't run their legacy Windows software.
So ARM has become the processor associated with "No you can't". Whereas the Intel brand is associated with "Yes, you can".