You\'re looking at it purely economically, which IMO, is the wrong way, especially when considering character development outside of gear.
What you said may be true, a tiny bump in stats on an item having an enormous effect on the price, but I think this is a bigger reflection on lack of real gold sinks and poor drop rates, not actual item worth/impact.
We all know how hard it is to farm upgrades yourself in the current D3 build, so even getting an infinitesimal bump in whatever stat is hard to come by, factor in the lack of true gold sinks, and you got an economy that\'s willing to pay sky high prices for bumps in stats whose effects will likely be negligible. I call this poor game design overall, not calculated progression with the end game in mind.