I would guess Canon analized what the optimum distance would be. Just like Sony was trying to make a statement with "Smaller is Better" and painted themselves into a corner with a small diameter mount. Who knows about the Nikon flange distance, Is there any technical advantage to it? Does it make the body too thin? So far I think Canon has shown vision. They got burned really bad with the Canonmatic R cameras and swore never again. They look at what is being done, wait and see how they can do a whole lot better. Look at the EF to RF transition, smokes Nikon completely.I wouldn't say it that radically but I agree, the RF mount has a huge potential. On the downside, Canon's flange focal distance is a bit bigger than the competition: 20mm vs 18mm (Sony) vs 16mm of Nikon's new Z mount - which gives a lot of freedom to adapt lenses. In fact, it looks like both the old players in the camera market now got some strong cards in the ML FF game. More competition will drive technology, so all of us customers will profit.