[citation][nom]skligmund[/nom]WinXP is going to be like DOS, in the fact so much is designed around/for it, that it will be around for a very long time out of necessity.[/citation]
You're very confused. Win XP is just a bad version of Windows 2000, which was a good version of Windows NT. Win XP is like saying DOS 3.3, it's just a version that was around for a while. PC-DOS (or MS-DOS) was a family of operating systems, Windows XP is part of a family (Windows NT).
PC-DOS is still around because it's simple and works in Real Mode. Windows XP isn't simple, and works in 386 Protected, or x86-64 mode, just like Windows 7.
The interesting thing is, people didn't like XP when it came out. Now, with time, people somehow think it's good. It was a bloated version of Windows 2000, with a bad interface that people changed back to 'classic view'.
Microsoft does stuff like this to make more money (not a crime, or necessarily even a bad thing). Think about it. If you have a whole bunch of hardware out there that can't upgrade to your operating system with full function, you suddenly open up a lot of possible machines to upgrade. Some wanted the security of XP mode, and many, many Pentium based Conroes and Penryns sold, so they make their OS more attractive for a huge number of machines, and that increase potential upgrades.