John Gruber, on why Microsoft needs to be the one making Surface (and not a third-party like HP or Sony):
The intention is obviously to slow the iPad down, but the radical shift in Microsoft’s strategy is about the fight over the profits that remain after Apple’s. The math no longer works out for the Windows you-sell-the-hardware-we-sell-the-software model. It works for unit share (cf. Android), but it doesn’t for profit share. Nothing works sustainably in business without profit — profit is the oxygen companies breathe.
His take and Horace Dediu's (who could ever argue with Horace?) make perfect sense to me. Microsoft is now doing what Apple began to do in the early 2000s. Begin chasing profits not marketshare.