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First of all, I'm not a PC fan boy. In fact, I'm in the market for a new machine and am considering a Mac for the first time since the early 80's when I owned an Apple][C (technically not a mac but it's still an apple). I am also willing to concede that Macs are better machines. Most importantly, you can get more done with less machine because of Mac's efficiency compared with DOS and Windows.
That having been said, I still don't buy the cheaper argument.
1) The computers compared are not on par with each other. For example, 512k versus 2 gigs of memory is not comparable (though I concede that processor speed was on par).
2) While Macs definitely maintain their value more than PCs (here the foreign car versus American car paradigm might be more accurate), the computer resale market is just not that attractive to the average consumer; the same group that is least likely to pay the premium for the Mac.
3) Your article doesn't take into account compatability issues. If we were all studio engineers, we'd all own Macs. But, most of us don't deal in complex audio visual stuff. The kind of home movie editing and garage recording that the average consumer does is PC acceptable. While Mac's may have better software, it's more expensive and the difference is becoming less dramatic between platforms as these applications become mainstream. Now, if you are a gamer or use some other less than mainstream computer application, you might not be able to run it on a Mac.
I'm not saying Macs aren't worth the price. I'll even go so far as to say Macs are significantly better machines, all things being equal. The thing is, all things are never equal. And, the factors that you cited that create value in the Mac platform aren't what appeal to the average consumer. To the budget conscious purchaser, PCs are still the better deal. Though, that may not last long.