I think Canon has been putting a lot of engineering manpower on the RF gear for longer than we think, so the release of lots of good lenses quite rapidly is no surprise. They made the decision to jump into FF MILC, and they are going to do it right.
I think the R body was rolled out so they have something in that market segment partly as a placeholder, partly to see the reaction. Plus for the vast majority of people, it is a great body, essentially a 6d3. The 5d and 1d bodies will be here in the next 1-2 years I suspect and they will be “mature” a lot faster than people think.
Having said that, DSLRs aren’t going away anytime soon. The EF lineup is already great, so it makes sense to put the effort into the future. Because at some point, R will supplant EF.
I’m holding off on any gear purchases until the body I really want, a 5dsr 2 equivalent, comes out. I’ll buy one, and use my EF glass until the R version of those lenses comes out. I’ll keep my dslrs for non landscape stuff like birding until the R bodies catch up.
I guess we’ll see how long all that takes, but I bet it’ll be a lot quicker than most think. So time to save up now lol....