PBS's Bob Cringely:
...the only company that truly benefits from Boot Camp is Microsoft, because they'll get to sell a retail copy of Windows XP for every copy of Boot Camp and retail XP makes Microsoft about three times as much money as the OEM version.
Daring Fireball's John Gruber:
Microsoft may not even “lose” anything at all, because customers driven to the Mac for this reason must also buy Windows if they want to run it.
Who are we kidding? I have no numbers to back me up, but if it were possible to count all Boot Camp or Parallels users and find out where they got their copy of Windows, I'd bet that 90% of them did not buy a new copy for the occasion.
At the very least, they'll use a copy they already own, either if they bought XP or it came with a system. More likely, they'll get it from work, a friend, or online. This is especially likely since XP was introduced in late 2001 but SP2 has only been available since late 2004/early 2005—it's probably safe to say that of those who did buy a retail copy of XP, the majority don't have SP2. (SP2 is required to work with Boot Camp which, since it's free and comes from Apple, will probably be the more popular choice, even though you have to reboot to use it.)
This doesn't really have anything to do with how good or bad Boot Camp is, and I'm not making a big statement about software piracy (arrr, matey!), Windows activation, or anything else. I just think it's funny that many columnists (more than just the two I quote above) are making a big deal about how Boot Camp is really a good thing for Microsoft since they'll sell more copies of Windows. Yeah, sure. If the total sales of Windows XP to Boot Camp and Parallels users amounts to more than could be explained by normal statistical variances or a rounding error, I'll be shocked. It all just reeks of justification/rationalization, like they're trying to convince themselves that Boot Camp won't be the end of Apple, Mac OS, or good native OS X software.
Microsoft makes money at a rate that humans can barely comprehend. (I think I recently read that their profit is a billion dollars a month.) Almost every PC sold comes with Windows on it. Retail copies of XP might cost 10x more than the OEM version but I bet there are 100 PCs sold for every retail copy of XP sold. Maybe 1,000. MS Office is a huge cash cow, and they make tons of money off expensive things like Windows 2003 Server and MS SQL server that are sold to businesses everywhere. Do the math: a tiny number (Mac owners) times a tiny number (percentage who own Intel Macs) times a tiny number (Mactel owners who will use Boot Camp or Parallels) times a tiny number (number of BC/P users who aren't going to just install it, look at it a few times, and never use it again) equals a very, very, very tiny number. Even if every single one of these people did buy Windows, it'd still be an insignificant amount.
No one who currently makes Mac software will quit making it now that we have these new options. First of all, it's only good for Mactel owners. Secondly, it requires either a) shutting down everything and rebooting (Boot Camp) or b) buying a $40 product. This is a great way to run software that never has been and never will be available for Mac owners (everything from MS IE 6 to various high-end CAD packages to custom-built, Windows-only business apps) but I guarantee you no one--not even Microsoft--who makes Mac and Windows software will say "We're going to quit making the Mac version. Buy our Windows version and use it with Boot Camp or Parallels."
Long story short: Boot Camp is very cool, but it won't change the world, it won't kill Apple or MS, it won't cause a flip-flop in the marketplace and give Apple 90% market share, it won't spell the end of good software for OS X, and Bill Gates won't finally retire now that he's made all this extra money from all these new Windows sales. It is just a neat little trick that will allow some geeks and a few forward-thinking IT departments to get a little more out of their hardware.