> there are no guarantees that AOSP even works without Google's magic proprietary mojo

What do you mean by this? If you mean in the market, it can work. Amazon's devices are proof. If a manufacturer is shipping just AOSP, it needs to have a working complement to Google's suite of apps or it needs to have a different value proposition altogether.

> CyanogenMod had to develop the missing pieces when Google sent their C&D over the proprietary bits

What "missing bits"? They were shipping Google's suite of proprietary apps on top of their AOSP-based ROM and they stopped after the C&D.