Your comments make no sense. You can build a high quality PC for under $1000 that will last as long as the equivalent Mac. The whole point is that the HARDWARE *IS THE SAME*. Only the OS makes a real difference.
And this idea someone said on here that Mac users don't want upgrades is cyclical in nature. You CAN'T upgrade all Macs except the MacPro so THEREFORE "Mac users EXCEPT MacPRo" ones "don't care about upgrades". Well, how can they care about upgrades if they CANNOT get them PERIOD anyway??? It's a ridiculous argument. Maybe IF Mac users COULD upgrade, they WOULD upgrade instead of buying ANOTHER $2000+ Mac every time they need slightly better 3D graphics.
The old saw about building a PC is incredibly tiresome. Try building a laptop from scratch.
And your incredibly naive to think the hardware is the same. Yes, the mobo and cpu might be the same. But the case, screen, and testing to make sure it all works together are not. But whatever.
I could also build my own house and save a pile of money. Who the hell cares.
Guess what, my time is money. While I can easily build a PC and have done so in the past when I had more time, I could care less about building one today. You might save a couple of hundred dollars, AT BEST, on component costs. For me, those savings would be gone in about an hour and a half in time. Factor in build time (about 2 hours), shopping time (1-2 hours at least on the internet, longer going to a store). And hope that every piece works together the first time, with no driver issues, or else your looking at an even longer build time.
99% of people that have a computer did NOT build it themselves. So pointing out that you could build one for less is worthless.
As for upgrading a Mac being cyclical thinking, you are misusing the term. However, I understand what you are saying. But you are wrong.
For one thing, because a Mac Pro or any other tower Mac typically is a fairly powerful system when bought, it has less need for upgrades to stay current. A typical PC user that upgrades is cash poor and upgrading over time, typically because the PC is too slow at some task. Well guess what, as you point out, a Mac Pro is expensive. Someone that buys it isn't going to need to skimp and save to put in a new video card after 2-3 years. They are just going to buy a new Mac.
I've owned 4 tower Macs, all bought new. The ONLY things I worked on on any of them were RAM, and hard drives. One, I added a new video card and one I added a $20 USB 2.0 card. And when they got too slow, I just bought a new computer. I could have replaced the CPU. Why bother.
Again, what you seem to be missing is that, in reality, NO ONE really is interested in doing any hardware work more complicated than installing RAM. And many pay to have someone else do even that simple task. Mac users, and most computer users, just want a computer to work, much like a telephone or TV. They just want to turn it on, do their thing, and turn it off. When it becomes outdated, they just replace it. This isn't 1992, when most computer users were hobbyists and most tinkered with their PCs. It's 2008, where basically everyone has a computer. And many don't even know how to open one.
As for the hardcore, who build gaming rigs, constantly upgrading, they are a dying breed, just like PC gaming. And a Mac user is NOT interested in finding what video card will actually work with Crysis and installing it. They will just have a 360 or PS3.