You can't base the new MP prices off that. If you look at the price differences between the xeon 5570s and the 5670s, the 5550s and the 5650s, and the 5520s and 5620s, there is hardly any difference between them when they first came out.
Basing the 2010 prices on that is total crap. Sure the components have gone down, but Apple hasn't lowered the prices, they are still selling the Mac Pro as if the CPUs are brand new, that is how they have always done their business.
Sure I can, Xeon CPU pricing doesn't change over it's lifetime. Very few Intel processors do, they tend to just be replaced.