One explanation that I find simple enough is that Apple wants to generate more profit from the juicer segment of the market: the workstations. Especially when they have probably one month advantage before the competition starts offering equivalent models. That's common practice.
I would say they're generating it with the latest models of the Mac Pros.
We can argue all we want on perceived value and Apple's markup, but there is no way that anywhere near 89% of the baseline Mac Pro is component pricing. There is an extreme markup on these models that goes beyond anything I can remember in the past.
It makes you wonder if Apple is trying to milk everything it can out of the workstation line in order to account for potential diminished sales in the consumer line.
Pricing totals taken directly from Intel's ARK Web site (bulk pricing per 1,000; it's likely that Apple pays even less):
New models (Early 2009)
Mac Pro "Quad-core", $2499, One 2.66Ghz Intel Xeon W3520 ($284) (Cheapest Nehalem XEON Intel offers) or 11 percent of total price.
Mac Pro "8 Core", $3299, Two 2.26Ghz Intel Xeon E5520's ($373 each, $746 total) (Mid-range XEON Intel offers in the "E-series" line) or 23 percent of total price.
Previous models (Early 2008)
Mac Pro "Two 2.8Ghz Quad-core", $2799, Two 2.8Ghz Intel XEON 5462 ($797 each, $1594 total) or 57 percent of total price.
Mac Pro "Two 3.0Ghz Quad-core", $3599, Two 3.0Ghz Intel XEON 5472 ($1022 each, $2044 total) or 57 percent of total price.
[iMac processor pricing removed]