I don't see this as being a huge thing in the future... fewer and fewer people build their own PCs or buy from small vendors.
Back when I was just getting started in computers, my first build was a P 133, 64mb edo, 2gb hdd, S3 ViRGe VX, and back then, if you were "in the know" you built your own box. These days, its easier to just buy a Dell and option it out, for most people.
And when you buy a Dell,HP,Compaq, etc, you automatically are going to get a legit version of Windows.