The photography world is not going to abandon FF for MF. Yes, bigger sensor makes for better quality images, but the size of everything grows to the point where it becomes unwieldy for many uses. Studio work... Yes. Weddings.... Yes. Architecture and landscape, yes. But for wildlife photography, sports, and anything else requiring long lenses, forget it.
MF is probably a viable market... FF will remain a viable market... But APSC? Right now, APSC offers two advantages, price and reach. As ability to make larger sensors at a reasonable price improves, the cost advantage disappears. As pixel counts grow, FF. sensors could put the same number of pixels on target as a crop camera, and destroy the reach advantage. I thing they will be around for several more years, but ten years down the road Many FF shooters will be MF, rebels will be FF, and there will still be high end FF cameras.
I hope they make the new MF cameras mirrorless. If they were you would have no size increase from current SLR cameras, and using on-sensor focusing would get rid of faulty AF issues, and it would mean wide angle lenses wouldn't need to be retrofocusing.
It would be cool to see if they started with both SLR and mirrorless cameras and an equal set of lenses for both, then the market could decide which system is better.
Do I have to point out that the whole point of a DSLR is the mirror?? You don't deserve MF if you haven't got a clue what it's for. The whole point it's for a professional market. Not a mirrorless market & not a rebel market...
"oh no, Canon/Nikon are abandoning me and I've invested all my money.." $500 in a rebel and $150 in a lens isn't investment, it's a plaything.
"ohhh, i don't want a big camera like a 5D because of my weak weedy arms..." the 5D is quite a small camera if you've ever used a Cambo 5x4 on a job. more so if you've shot 10x8.
some folk seem to not understand which side of the fence they fall. FF (as was 35mm) is a compromise on MF (Mamiya/hasselblad) but because of the ridiculous price of the hasselblad system it renders the 1Dx as what is perceived as the top end of the market. It's no where near. Sure I love my 5Diii and the IQ it gives me but imagine that tech (or the 1Dx) in medium format with more amazing glass? and if it comes in at half the price of a hasselblad it'd be brilliant news for the industry. not for the hasselblad users though. Hasselbladrumours.com will be up in arms