No, they did that by being unethical. Like taxing PC makers for each PC sold, not each copy of Windows installed. Among other shady things. (And of course, IBM pretty much handed them the license to print money in the first place)
Anyway, one big mistake MS has made so far was not making enough 360s to meet demand at launch. They also probably should have stuck with the original Xbox - pc hardware model, as they could have gotten more bang for their buck and have easier development.
2 SKUs was seemingly pretty stupid, though now it does let people say that the PS3 is twice the price of the 360.