It means that, if microsoft starts to make its own hw also for the pcs market, there will be a big problem for other manufacturers to stay in the same market.
Apple may live in a world where it is they only manufacturer for the hw in which runs his sw because they have create the first recognized brand in the world and they are like the "cool people of tecnology", but microsoft can try it? Looking at the actual marketshare of wp8 and surface RT or PRo, i think nope.
But they have strong points too, and the next version will probably be better. They are still experimenting, trying to figure out exactly they want to do.
Market share right now means nothing.
I wouldn't want Intel to think I am to be dependant. The Surface RT line makes a statement. A weak one but it is nonetheless a statement.
Dropping support for the OEM's in the Phone and PC space would be an interesting move, which I think they could carry off quite quickly. I don't think they are headed in that direction myself.