And the motor coach costs quite a bit more than your standard minivan.

There are quite a few tradeoffs that go into the decision of where to draw the line between application specific and generic processing. Processing speed, cost and flexibility/performance all play off against each other. For example if you want more speed you'll either have to pay more or give up some flexibility. How well you strike a balance between those factors essentially determines how well your product will sell. If your product has what people want at a price they are willing to pay they'll buy.

I also think that the Sherwood problems are resource related. I'm sure the algorithm had to be simplified significantly to get it to fit on the 972. A change of basis from one vector space to another is dicey enough when you have a linear time invariant system. Start throwing in nonlinearities and I wouldn't be suprised if the simplified solution wouldn't converge for a large number of cases.