Probably because no one had the D800 in stock, and low supply means high demand which means no market drive for a lower price.
The stock has been good for some time now but I still have not seen any shocking deals on this body.
I thought $3500 was not unreasonable. The IQ of a 5DII (already excellent) coupled with the AF system of a camera costing >$3K more, plus 6 fps shooting speed? That's a powerful combination. If I had any interest in purchasing a 5DIII, would I want it to be cheaper? Of course. But if I had been interested in purchasing a 5DIII, the $3500 price would not have affected my decision. Amortized over a 3 year life of the camera, $500 becomes something like 46ยข per day. My morning coffee cost 10 times that. Just sayin'.
Well, the street price drop is more than $500 in the US and considering Canadian online buyers it is around $1K for us. I do realize the MSRP was not an issue for some. However, this is not what i am talking about. Yes, the extra $500-$750 might not be a big deal for pros who have this cam as a money making machine, or for some who can afford to pay even more than that without any significant financial impact. But consider D800 sitting next to it at $3K and consider over 800 Canon units which Adorama easily moved in just a couple of days at a $750 discount. I don't think that $2750 is just a pocket change for many in these hard economic times, however folks jumped on this deal right away. Nobody is expecting to have MKIII discounted into oblivion, but people are ready to spend close to $3K of hard earned cash for this item. Again, this is not just about purchaser's expectation of a cheaper price. Its about current market situation (mostly direct competition from D800).