i seriuosly don't see why upgradability is such a grievance...
i have a power mac G5, and i've only upgraded as much as i could do on an iMac any way: Ram and hard drive. the video card... works for me. it's two years old and i can play Quake 4 and Call Of Duty 2 on it just fine, with all the details turned on, pretty much. when the porcessors get too slow, it;'s time to get a new computer anyway.
people put far too much importance on upgradablity. only idiots upgrade cars, for example...
There's something to that, I have generally not upgraded most of my Macs but mostly because it was impossible, difficult or too expensive.
When the Mac didn't have a CD burner or a DVD drive or dual monitor support or needed USB 2 or more Firewire ports, it was a real pisser. Even replacing the dead battery on my son's iMac DV 400 was a nightmare and took hours of research and benchtime because of the battery's inaccessibility. We gave up on removing the last 3-4 layers of casing and I juggled the battery roughly into place while my son, with his smaller hand, pushed it gingerly into place. Even then we dropped it into the case several times before we finally succeeded. The current intel iMacs are inaccessible except for RAM.
Mac users are not conscious of how many PC users actually progressively rebuild and replace bits of their computer during its working life. Upgrade kits take the PC case and replace the motherboard whilst retaining the drives etc. This keeps even an older PC well within usability for most of its life. The parts are bought for a pittance and aren't subject to the weird and undocumented incompatibilities that Mac graphics cards, for example, seem to have.
The expensive iMac mini's "marvelous ability" to combine with a PC user's monitor just got strange looks from PC users who for a pittance take a lot more than that from one model to another.
Apple has at most times made it impossible to install their particular OS onto anything but a small range of models. The rest would be incompatible, either too old, or too new, or too slow.
Compare the options for installing current versions of iTunes and Quicktime on anything from Windows 2000 to the latest WXP, with the extremely narrow range versions for each iteration of Mac OSX, or OS 9. It's a protracted google search each time to discover what goes with what.
Apple is not user friendly. Just look at how many expensive upgrades of hardware/software Mac users have been forced into over the last 5-6 years due to Apple's changes in OS, hardware and peripherals. In every case Apple users had to put up with major expense, retraining, incompatibilities, slow downs and screw ups brought on by Apple's changes in direction.
The latest Macs show alternate improvements in compatability and upgradability then take another huge lurch back. All the time dancing all over the place with model names, numbers and identification. The uncertainty of what does or doesn't work is what leaves most users reluctant to even try to upgrade even if it is possible.