A couple of posters have already made this basic point...Microsoft is trying to "give away the razors, and sell the blades and shaving cream." Second, if they can establish a monopoly here, they will. Third, don't EVER count MS out. They were "out" of the word processing business (WordPerfect), the spreadsheet business (Lotus 1-2-3) and the internet (Netscape). Now they are not. :-(
Finally, and this is the most interesting point to me...especially on this board.
Everyone (and it really seems like EVERYONE) has been lobbying for (or speculating when) Apple will port OS X to x86 (it can be done, and has been done in the past...technology is not the problem here). They point to commodity (junk) hardware...blah, blah, blah. And yet...and YET...Microsoft appears to moving in exactly the opposite direction...INTO hardware. Note, XBox is not the only foray for them. See this article:
http://zdnet.com.com/2100-1104-938110.html.
If I were Dell or Gateway, I'd be very nervous.
Microsoft is looking for new ways to grow its revenue. Its software sales are flattening. So, why not grab a bigger piece of the customer's pocket book. True, margins on hardware are slimmer. That is assuming you don't have a monopoly. Look at Apple...30% margins. Why...because if you want what Apple offers there is only one place to get it (Apple has a monopoly too...though not so much in the classic sense of it.)
Microsoft WILL be a hardware player. No doubt of that. And when they realize they can control the whole picture (much like Apple does)...they will. The process may be slow...but it will happen.