"Overpriced" is little more than your opinion. If apple will price things such that it makes the most money possible. You can't go pretending to quote the laws of economics and ignore this simple fact.
As far as the pro goes specifically, it is "old" likely because Apple nearly axed it and back peddled. However, they weren't ready to just stop selling a mac pro, so they gave it slight spec bump and said "here, maybe we'll do something in about a year."
Now, a lot of people were obviously a little POed. Th you ey wanted Sandy Bridge, new graphics card, TB, etc. But, as you say a not insignificant portion of the pro market wants or needs a OSX workstation. And so, the forces of supply and demand for the Mac Pro start to be visible, do they not? Apple can get away with higher pricing on an "old" machine, because of a specialized market need, the OSX workstation. So, what you think is overpriced, is actually just those silly little laws of the economy spouted off so ignorantly coming back to bite you in your rear.
Unless of course you have some sort of data to present to Apple that they would actually make more money by cutting the price of the Mac Pro, I'm going to go on assuming that Apple's insane profits suggest they know how to price their products, iToy or Mac Pro.....