Problem is your average Joe Bloggs is unlikely to be buying it for the correct reason as far as licensing goes.
Mixture, I think we are on the same wavelength here - what is feasible and what is legal do not necessarily overlap!
MS does seem to recognise that Joe Bloggs can and does build his own PC, and is reluctantly admitting that that qualifies as an OEM install. I guess they figure they are better off with the revenue from an OEM license than no revenue at all. After all, a lot of technically competent bods might otherwise jump to Linux!
That's just my opinion, based on what I have read about the topic.
SD