I know professionals with big investments in lenses are going to be the hardest to move to a new system. Even with the R&D done, releasing an RF and EF lens to cover a particular market segment is going to be more expensive. I don't know the specifics of it, but if you released the exact same lens with two mounts, you're going to have to compromise on one or the other and probably both.
Even running parallel lines or changing lines over from one to another is more expensive. At some point in the future, they're going to start making new RF lenses that aren't going to have a corresponding new EF version and eventually, they'll stop production on old designs. They stopped making FD lenses even though they must have had a big installed base. They have lenses that they produced for at least 8 years so the cycle is going to be very long.
I haven't researched anything to figure out what optical advantages there may be to the new geometry of the mount and the rear element being closer to the surface of the sensor and I was hoping that you knew so I wouldn't have to actually put that effort forth,...
I don't expect any pros to switch. I'm hoping that as RF versions of the legendary EF lenses come out, some population of suckers who have to have the latest and greatest gear, even if the advantages don't justify the cost. That way the price gets driven down and I can pick them up for cheaper, like when a new generation of a lens comes out and the old, still awesome previous generation, drops in price.