I'll get technical here, even though I don't know how many angels can dance on the head of a pin.
It's possible that if someone sold a Linux distro for $300 more people would use Linux, but I doubt there would be a direct cause and effect. I read Groklaw and comment a lot. I won't deny some of the criticisms of it are valid but the people who run it do a lot of serious research about legal issues involving Open Source and Linux. If you go to the home page in the right hand column there is a link to something called MS Litigation. I strongly recommend clicking on it and reading it. It deals with the most recent anti-trust cases brought against them, and some other issues.
In essence you shouldn't need Groklaw to understand that one reason Linux doesn't have more market penetration (as Ubuntu) is because Microsoft is trying to make it as expensive as they can to run it. They've done this to everything, which is a reason we're talking about Ubuntu rather than the BeOS, say.
I won't talk about what a pain Gnome has been since they introduced Mono and MS technology except to say that while KDE has always seemed so bright, peppy and utterly without inhibitions it always reminded me of someone on Ecstasy it has become my primary desktop.
Meanwhile Steve Ballmer has claimed -- while refusing to be specific -- that "Linux" infringes on 124 or whatever the number is patents. Does he MEAN the kernel? Linus Torvalds has asked, "Just because Windows does it what makes you think that is EVER a good idea?" and this actually does seem to be part of the design philosophy behind it.
Microsoft is abusing its monopoly power to keep Linux off the desktop. Whether Linux should run on everyone's desktop is another question. There really should be room for an OS specifically for power users.