You may be paying a lot less for MS Windows than you think. The tiny non-profit where I volunteer is paying something like US$40 or 50 for XP Professional. I didn't negotiate the deal, but it's real, honest-to-goodness, legal XP including CD. I have no idea what one goes through to get a deal like this.
I think this is some indication of the sort of price that the hardware people pay for XP.
You may not like the thought of paying even US$40 or so to MS, but it isn't a huge sum. [Unless you're MS and sell millions of copies.]
Perhaps it is a little like the old days when Kodak practically gave away cameras it order to sell film. MS see their profits in add-ons and a low-ball OEM Windows price could keep the Linux wolf at bay.