> My educated guess is that it's part of lowering costs for themselves and reducing the need for hardware vendors to access their source code.
More likely, they're paying a subsidy to companies that build these devices in order to get them to use Windows 8, perhaps to the extent that they're taking a loss. The end consumer product might be cheaper than the hardware cost.
Sometime tells me, the specs for Windows 8 device are going to need to be higher than for Android. If they want to be cost competitive, they'll have to subsidize.