are you talking about quadro or firegl cards?
They are already there (since years), have much vram, are 24/7 able, generate less heat and are very expensive.
Indeed. The current price mechanics for GPUs comes from their MASSIVE volume of sales. I believe the 58xx series sold something like 20 million GPUs (not an exact number, but certainly feasible). So if it costs 50million dollars to contract a fabrication facility to produce their chips, then you can see prices like $200 for a 58xx card on the shelf.
Now if it costs 25million dollars to contract a fab plant (their time is expensive) and you expect to only sell say, 200,000 GPUs to miners, then it's not unreasonable to expect to see prices be thousands of dollars on the shelf, like the firegl cards. Until you see adoption of bitcoin mining on the level of video gaming you won't see cards being optimized for mining at the same prices, and of course then you face the double edged sword of insane difficulty killing that benefit.
You forgot design costs, board costs, distribution. It'll cost tens or hundreds of thousands of dollars per card if the pro cards aren't basically just the consumer cards.
This is why military hardware costs so much. They make so little of it.