Macs 5 years ago are entirely different than a Mac today. Reviewer after reviewer rate the Mac OS as the most advanced OS currently on the market.
When was the last time you used a Mac..?
With regard to "one reason is trying to keep up with OS changes that aren't supported from one to the next"
I hardly think progress is a bad thing. Perhaps your happy with Microsoft's unchanging bloat-ware.. but an increasing amount of people are switching to Macs because they are sick and tired of working for their computer...they want their computer to work for them.
Go spread FUD and flamebate somewhere else...or at least educate yourself before you post something that makes you sound woefully uninformed.
Every major piece of software that is available for the PC has a Mac counterpart. Furthermore, Mac software is exceptionally written..even the freeware.
I was introduced to computers through Macs. I bought a lot of them for myself and a staff of graphics people. I abandoned Macs about five years ago and recommend that move to everyone. Here's why: they cost too much for what you get, Apple regularly changes OS and leaves you holding the bag with a ton of upgrades you have to purchase, don't believe they are problem free - I know a lot about computers and software because I HAD TO owning a Mac, there is little or no selection of software and programmers aren't writing for Macs (one reason is trying to keep up with OS changes that aren't supported from one to the next). Every program I owned on the Mac, I can get in Windows. As long as I pay attention to what I'm doing I run virus free and with very few problems on all of my Windows machines. If it's about being "cool" certainly buy a Mac. If paying too much and having fewer choices gives you a certain feeling of superiority - certainly buy a Mac.