In reality, 35mm can never complete with MF as long as they have focal plane shutters. All 35mm cam's need to get on with electronic shutters or a set of LS lenses but why not just get MF then?
Hmm...I don't think I'd call an electronic shutter better. At least, they won't be better until they are all global shutters that instantly shift all pixels into a background per-pixel memory. Most current electronic shutters on DSLRs and Mirrorless cameras scan, so exposure isn't guaranteed to be the same from bottom to top. A global shutter would need to be high end as well...there is still row activation with a global shutter, and still that scanning. They can shift the pixel value into the pixel memory faster than a full readout, but there is still that lag. For longer exposures, that doesn't matter as much...for action photography, the lag matters. A nice high end global shutter design, the kind used in digital cinema cameras that can operate at thousands to tens of thousands of frames per second, is the kind of design I'd really want in a DSLR electronic shutter...at least then, I'd know I could use it for high speed photography and not have to worry about a slight exposure gradient across my images.
As for leaf shutters...they have their cons as well. I think the key benefit everyone wants from a leaf shutter is the ability to, at least theoretically, sync at any flash speed. At times I've read about how leaf shutters can operate at several ten thousandths of a second, and still sync. A lot of that is simply not true, at least, not in the context of DSLRs. Most DSLR-sized leaf shutter lenses sync at 1/500s, a very few have synced at 1/1000s. The only leaf shutters I know of that have synced at 1/20,000s or faster are really tiny ones in small compact cameras.
There is also the issue of inconsistent exposure. Because a leaf shutter opens in the center, flowers outward, then flowers back inward, you get less exposure at the periphery and more in the center. That effectively guarantees vignetting in every single image...additional vignetting, on top of any that might naturally occur due to lens design.
Leaf shutters, good high end ones, are also complex and costly to build, and they would have to be in each and every lens. Personally, I would rather NOT incur the additional cost of having a leaf shutter built into each and every lens I buy...I think its more cost effective to have the shutter, whatever design, elsewhere, and allow lenses to be cheaper.
As for MFD, I guess time will tell. Sensor area is the ultimate key to better image quality, but the older sensor designs used in say the Hasselblad H3D and H3D II were similar in design to Canon's current sensors. They had as many problems with shadow noise as Canon cameras...lots of it, banding, etc. The current H5D-50c still sells for $28,000 just for the camera, and it's at least a few thousand for a lens. Canon would need to compete with the H5D-50c, not the old H3D, if they wanted to break into the market. I honestly don't see Canon doing it for all that much cheaper than Hasselblad, and if they did, they would likely be taking a loss on the products just to be competitive (especially if they aren't using a 300mm wafer fab...I think there was a rumor a while back that Canon might be either migrating to a fab that does 300mm fabrication, maybe taking over some of the capacity from P&S fabs that aren't producing as many compact cameras...or maybe building a new fab, but to manufacture MFD size sensors, they would have to take capacity away from something either way).
The benefit of medium format film was the cameras were all still designed roughly the same way. A medium format SLR might have had some additional features, but there was nothing in particular that made them particularly more costly than smaller cameras...not as far as the bodies went. They didn't have the extra cost of manufacturing extremely low yield sensors that cost a fortune to make. The customer took care of paying the cost of the film. That's nothing to say of the IQ we can get from a "lowly" 35mm DSLR these days, let alone a digital medium format. It's a little unfair to compare a modern DSLR with the "cheap" 35mm film and cameras of yesteryear. Full frame DSLR image quality is now far superior, and digital medium format is again superior to FF DSLR.