I've been working in the industry for 14 years now and got started supporting the Win98-->XP transition. This all sounds so familiar to me. "Why' are they dropping Windows 98? XP is too slow and buggy!"
People seem to forget how long it took to make XP the OS that everyone loves today.
I wonder how many of the XP users here use the 64bit version? I wonder if the 32bit folks realize how much of their ram is being wasted by the asinine way 32bit XP addresses ram?
I wonder if they have just gotten used to the hard drive churning all the time, non stop, because of the way XP treats pagefiles (answer: like a baby treats a diaper)? I wonder how often they defragment their hard drive and other archaic "fixes" to resolve XP's shortcomings?
I wonder how many XP users just take it for granted that you need to reinstall XP every year and a half to flush the myriad untraceable crap that XP writes to the registry and hard drive and then seems to forget?
How old are the peripherals plugged into the XP desktop? Don't expect to find drivers online.
I will grant that if anyone is planning on installing Windows 7 or 8 on a system that they bought with XP installed then they are going to have bad times. The XP OS is 13 years old! It is as polished as it can get and it is still problematic in a number of ways.
I'm betting the autocad issue mentioned here has more to do with an old copy of autocad than a new OS.
Also, for the clingers, try the free Virtual PC for windows 8 and install your precious XP in a virtual environment or, better yet, P2V your existing machine to the Windows 8 Virtual PC and have a fully portable copy of XP that you can move from PC to PC as you upgrade.
If Windows 8 is too much change for you, at least upgrade to a Windows 7 machine and P2V your old decrepit system to it.