Because the iPad 2 is a dog compared to any of the other models. Apple is a quality brand; the mentality used to be that it didn't matter what Apple product you bought, as it would always be something that would last and was always fairly updated compared to last year's model.
This is nothing short of exploiting consumers who are paying far too much for a product that should arguably already be obsolete. I genuinely can't see how they can justify this pricing for an iPad 2. Apple claim to only sell products they'd use themselves. Say what you want, but Ive/Cook would be tearing their hair out if they were stuck with an iPad 2 as their only tablet.
It has more to do with existing approvals and standing orders. iPad2 is approved w/ the FAA, and popular with educators. Those buying in bulk will surely get a severe discount when doing so, and Apple is able to give it to them with the iPad2.
It's not really geared at consumers, and continues to stick around for the bulk-buying customers primarily.