I agree with you that when I talk with a prospective fine art print buyer I sometimes get the question of what do you shoot with. Some of my print sales are requests (specific skylines or area icons) and my 1dsII just doesn't wow them anymore. This even when I can show them a 90" print made from stitched files.
On the opposite side of the argument I do think that for MFD to be long-term profitable it will require higher sales volumes. That is where my type of shooter also plays a roll. I make enough on sales to help offset my equipment addiction for my landscape shooting. For the average shooter to move up to MFD the costs will need to come down on the backs to generate higher sales volumes for Phase or Hassy. Otherwise Canon/Nikon will win out on the cost/benefit analysis. I am purchasing a MFD (30 or 39mp) system this December. I can only do this because I have a good job and an understanding wife.
For most in my situation (that I have spoken with) the prices are too out of reach to jump from Canon/Nikon to MFD. Phase One's latest refurb pricing is a good step forward for many.
Anybody that thinks about medium format digital loves photography. Whether they work with a 50 person crew or shoot landscapes at sunup by themself, you just don't think about these pruchases unless you really love photography.
Not talking digital here (god let's don't talk digital) but let's talk cameras.
If you had to buy one new, available camera to use for the rest of your life, what would it be?
After all, when you talking $40,000 digital backs, or $20,000 upgrades (oops I mentioned digital backs), you had better love the camera you put them on.
Two of my friends that are very good photographers.
Both do very well, have a lot of success, but don't think they don't keep a eye on the bottom line.
One shoots architecture and I think he's probably the best in the world at it. He recently bought two Alpas.
Now knowing him, I doubt seriously if it changed his work a great deal, but I do know he believes it bettered his work, so he bought them and though he proably won't admit it, he bought it because he likes it. It makes him feel good.
The second photographer shoots people and has owned about every film and digital camera made.
He is now back to using the Canons and they do the job, he gets the shot, but the cameras don't stir his soul and I am sure that he will eventually go back to a camera, (probably medium format) that makes him happy, because after all you just have one life and when you open that case does it glow, or does it look like a snapshot from a Big Box retailer?
Really, this isn't always about dimensions, weight, mtf charts, or pixel size.
It's about what makes you feel good.
I don't think any of us need a reason for that.