I started a thread about this over in the lens forum with my full thoughts on it. But I've suddenly realized, for lenses that do not benefit from the shorter flange distance of the RF mount, like pretty much any telephoto lens, you have to ask yourself, what does Canon even gain by moving them over to the RF mount, aside from pissing off DSLR owners?
The mount diameter is no bigger, there are a couple extra electrical contacts (big deal.)
Honestly, I forsee Canon continuing to make EF lenses for the foreseeable future, unless it's a lens that could benefit from the shorter flange distance, in which case they'll make it an RF and take advantage of that.
After all, you just toss an adapter on the back of any EF lens, and viola, it's now an RF lens. So why even bother changing the mount on a lens that doesn't get an optical benefit from doing so. People will complain that you need an adapter, but I suspect that this might be a lot smaller of an issue for Canon than it seems to be for us because they know that the adapter will work flawlessly and it's not just some iffy, stopgap solution the way that Canon to Sony adapters are.