Canon took a giant risk, but won big, when they built a lens mount from the ground up for their auto-everything SLR system. This, the EOS 630, is an early example. Check my updated review here.

Canon took a giant risk, but won big, when they built a lens mount from the ground up for their auto-everything SLR system. This, the EOS 630, is an early example. Check my updated review here.
You said it when you say that Canon took a big chance redesigning their lens mount, BUT it was pure genius…anyone that has stayed with the Nikon system for years knows that the smooth interchangeability of the lens mount is pure fiction! Many of my vintage lenses would even fit on the modern film bodies unless it was a model with a little flag that could be flipped up on the mount, which they slowly did away with as they went on. From Canon’s new lens mount on, they were the king for technology. I ended up switching almost every place I worked over to Canon gear after that.
As a hobbyist photographer, Nikon’s lens incompatibilities really aren’t an issue for me. But I can imagine how, as a pro, it was crucial.