I just don't think that's reasonable or realistic. They are two different machines, they are used for different jobs. You can not now, nor could you ever, expect to buy any camera that can do it all at any price, any more than you'd expect that from a vehicle.
Every time we have new equipment announcements, the conversations always go to costs, usability, costs, features, cost, brand loyalty and they turn philosophical.
I agree in the film days we never would think about having one camera to do everything, but in the film days a 35mm camera could never get to 70% of the output quality of 8x10.
Cost is always important but I don't think it's the costs that blurs the lines as much as the usability.
To be honest the Canons are just easy to buy and easy to use. The basic learning curve from a film camera (any camera) to a Canon is about 10 minutes.
The ability to easily flip through iso of 100 to 800 is crazy easy and the files look good. Not overwhelmingly jaw dropping good, but regardless very good.
The Canons aren't inspiring or thrilling cameras, but you can buy them anywhere, any lens anytime and produce virtually any look you could imagine.
It doesn't mean I am going to sell my medium format cameras tomorrow, but as the Canons get better the lines do get blurred more and more.
Post production blurs the lines even further. If your good at post, or you outsource to a firm that exceptional, few if any person can tell the difference between any medium format capture and a Canon file.
Shooting medium format, for any of us, for any priced production is an elective, it's rarely mandatory. I may chose to do it because I just like the look, or I may do it because I want the stability and speed of tethering, but the idea of going out to shoot an ad campaign around the world without a Canon in the bag (at least as a backup), is rarely if ever heard of.
Why is medium format more or so expensive? I have no idea, because I've been told it's the sensors, the dealer arrangements, the R+D costs, the limited market, but I assume it's all of the above. It may be none of the above.
Regardless if medium format is 2,3,4,5,6,7 times more expensive than the Canons I would love to see the backs and cameras do more. Better LCD's, higher iso, faster lenses at least the equal of the Canons would seem to be a given.
Maybe the latest announcements will all pan out and be everything that we need. At this stage it's always difficult to tell because information comes out in steps and we are probably months away before we really know, months after that before anyone gets the new equipment in their hands to work it hard.
Once we see photographs come from these cameras then we will know if it's worth the investment.
If the photographs that come from these new cameras are far and above anything possible before, then the investment starts to make real sense.
in the end It really is about the final photograph, not the process.