Assuming that it is true that loads of people are installing Microsoft Windows XP on their Linux-powered Dell Inspiron netbooks (which I'm not sure is true, since the original article didn't mention that), it doesn't really matter. A Linux sale is a Linux sale. When the Dell managers evaluate their future strategies, how much will they consider whether XP was installed post-sale? Very little.
And the same is true for Dell's competitors. If Dell's competitors see that they can move product in a down market by installing Linux on the machines, will they spend much time contemplating whether XP is installed on the machines? Probably not.
Most OEMs have small margins on their sales of all but the upper-end machines. Volume is what matters. Hence the power of Microsoft Windows. At least until today. For OEMs and pretty much everyone in the channel, volume is what matters. As of today, they will know that Linux distros have proven that they can drive one-third of that volume.
That is what really matters.
And it gets better. As Linux-related desktop sales increase, you will see more and more third party vendors, such as 2dBoy, port their products to Linux,
as maker of the popular indy game World of Goo has recently done.
Volume is king. And now Linux is seeing some significant volume sales.