$2500 is a little expensive in my opinion. Maybe the reason for this is that the A4000 isn`t available anymore but yet there is a huge demand for it at certain graphics/video related companies.
When Commodore went bankrupt some companies even advertised in Amiga magazines and offered to pay you more money for your Amiga than you had originally paid for it.
Disney for instance paid huge amounts to buy 500 extra A4000s for use as spare parts. Disney`s Dinosaur was created with using Amigas and the lead animator of that movie was quoted saying Amigas being the best machines Disney has for doing animations.