Look at B&N, they are fighting M$ in court because they cannot make a deal like the phone people did.
"HTC Pays Microsoft $5 Per Android Phone, Says Citi": http://www.businessinsider.com/htc-pays-microsoft-5-per-andr...
There is another aspect, a lump sum of 5-15$ per unit might look like a lot of money for M$, but over a 2y period thats not much. All that such a deal would do is to make the phone a bit more expensive, same as if another earthquake hit and some parts like CPUs or RAM became more costly. Carriers would easily swallow that for subsidized phones. All the search revenue, App store revenue etc. would still go to others like Google. And most important, the customer would be lost to M$ - If M$ wants to take a significant market share in mobile, collecting royalties on Android is not the way.
Also, 5-15$ is significant when comparing it with the manufacturing costs of the device (the iPhone 4S CPU is estimated at 15$ by iSuppli (http://www.isuppli.com/Teardowns/MarketWatch/Pages/For-the-i...).
Show me a line item in either HTC or Microsoft's quarterlies validating that?
It is interesting that virtually every agreement that Microsoft has achieved has been with vendors that sell Microsoft products.