Is the sole reason the MacBook contains a GMA 950 instead of something old, say a nVidia 6200 Go or equally dated laptop card, to keep it distinctly inferior on paper to a MacBook Pro for video uses?
I would think it is a money saving move. The kind of people Apple is marketing the MacBook to don't typically need a more powerful graphics card (students, web surfers...).
Perhaps. It could also be because it cements Apples relationship with Intel even further. The good thing about the GMA950 is that is uses very little power and costs next to nothing (no VRAM) so that may also be a reason.