[...] It is not a simple protocol.
But at the same time I can buy for less then 50$£€ a third party RF to EF converter from third parties (Meike, Viltrox, Comlite, etc, you name it) that enables any EF lens (third party EF included) to work flawlessly on R cameras.
So creating electronic stuff with electronic contacts that enables AF, IS (limited on 2 axis), etc, on R bodies seems pretty simple, and also allowed.
So I still don't see any reason for them (third party gang) not to make a RF mount lens with RF contacts (what an adapter is, and Canon allowed them since day one or so without any issue), but with EF protocols; they certainly are threatened by Canon in some way if they don't do it.
I can see Sigma or Tamron maybe wanting to bring to the market their top game lenses, having access to RF specific functions, like 1/8th stop control for video aperture, 5-axis-control for IS, etc, but I find very strange that smaller lens manufacturer like Viltrox and Samyang haven't already flooded the market with RF lenses with RF mount and contacts, with EF instructions...it's like adapting an EF lens with a third party adapter, with the difference that you do it directly on the lens barrel and of course take advantage of the shorter flange to use mirrorless optic schemes. They can call, brand and market them as "EF-R", or "AF-R" lenses, or whatever they want, if writing "RF" anywhere on the barrel and/or the box and the instruction manual is protected and forbidden.
Maybe RF is not a simple protocol, I don't know, but certainly there's another protocol, EF, that works wonders on R bodies, and Canon is certainly not going to cut the EF-on-R support tomorrow (or I would say EVER); so why don't use it? You can do EF lenses, you can do RF to EF adapters, just mix them and call it wather you want but RF.