Some of the increase can be attributed to inprovements in design and improved quality and service. However, IMO the biggest part of the increase is simply because they can get it. They would be fools to charge $500 for a bow that they know they cansell for$800.
Simple capitalism and supply & demand.
I've bought 2 new bows in my life and probably won't buy another one. The AT classifieds and the used racks at the local shops have everything I need and if I wait long enough I'll get the price that I want.
I love the guys that have to have the latest and greatest. They drive the market and supply the used bows that I'm looking for.
Now if I can just get a Barnsdale Ultimate X with the bamboo limbs for $200 I'll be set.