I’m not sure what would happen in your case. Microsoft’s business model, even the initial success of Microsoft, is dependent on the current structure, and I don’t think they could ever go the Apple way. All the manufacturers would vie for the supply contracts, creating a lot of competition (and associated technological advancement) to get them.
I don't see having only two possible buyers for computer OEM hardware, and virtually no direct retail market for the manufacturers being a formula for increasing technological advancement in the market.
If Apple's approach really is better, and Microsoft has been doing it all wrong then Microsoft needs to do what Apple's been doing. What are the consequences going to be if they do?