God knows MS could do with something, anything, that would fuel the market share of Windows 8. But making things difficult for app developers is not it. Nothing about this encourages sales of the OS or encourages developers to write for it.
It's not like the desktop situation, where pirated Windows installs maintain an incentive to keep people from experimenting with Linux on their commodity hardware. There are no commodity tablet devices out there without an OS. If you want a low-cost one, you get an Android device. In which case you are already using Linux, and nobody in Microsoft's traditional customer base is going to go to the trouble of jailbreaking Android to install a pirated Windows 8 even if such a thing existed.
Which doesn't rule out W8 security as a cynical ploy of some kind, but I suspect it's more satisfactorily explained by simple incompetence and laziness.