Because desktop linux is a suitable replacement for a 10+ year old OS, nothing more.

Yes, it will run fine on a ten year old computer. It also, unlike Windows, runs on supercomputers.

While Linux fans and critics obsess about Linux's failure to sweep Windows off the desktop, they're ignoring that Linux is winning everywhere else, and that when it comes to the highest of high-end computing, Linux rules.

Driving the point home, the top 10 fastest supercomputers all run Linux of one sort or the other. You have to go the way to the 44th fastest computer, the European Centre for Medium-Range Weather Forecasts box, which runs IBM's AIX Unix variant, to find one that doesn't run Linux.

Except for running Windows-only software, there isn't a single thing Windows can do that Linux can't. It isn't just a fine replacement for XP, it's also a fine replacement for Windows 7; Windows has slowed my laptop down so much in 3 years (slower every patch Tuesday) I'm putting kubuntu on it this weekend. It has functionality Windows lacks and the only thing Windows has that Linux doesn't is the ease of which it pisses me off, especially on Patch Tuesday. The fucking computer is tied up for forty five minutes or more for the download (can't do anything while it's doing that because that damned "I'm doing something! Look at me!!" balloon keeps popping up until you have to close all your programs, reboot, wait for it to not tell you DO NOT TURN OFF YOUR COMPUTER!, restart Windows, again wait five minutes while it says DO NOT TURN OFF YOUR COMPUTER!, then log on, then you have to reopen all your apps and files.

Linux tells you you have updates, you click "install" and keep on working. Rather than slowing the computer down, Linux updates usually make it run FASTER.

Windows is a toy OS.