I actually have no problem with Apple's prices. People don't buy a Rolls-Royce because it's a car, they buy it because it's a Rolls-Royce. Comparing the purchase price or mpg to a Toyota Camry is missing the point.
I build my own machines, and don't buy Apple products. However, I see nothing wrong with charging what the market will bear for an upscale product.
This would seem to be an ill timed article as the 6 core per chip Mac Pros are here this month. The cynical part of me thinks it is timed now to make it look like he took those into account (which he didn't). Also note the "* Estimated score" at the end of the performance graph.
I have a hard time making sense of those graphs since I don't see units or a scale on th y-axis.