Probably because of the very generous Ricoh "upgrade" offer. For the company, I would think that it keeps hoards of cheap K-1 bodies off the used market- a win for sales. If I had gone for a K-1 when it came out, I would jump on the deal for the upgrade for sure.
I guess I was suggesting that the relative lack of used K-1 Mk1 bodies might cause the price of new ones remain higher.