Considering Nikon released the Z50... I wouldn't rule out an APS-C RF model. As good as the M cameras may be, canon will want the majority of their customers to buy into RF simply because that's where they will have the profit margins. And they need an entry point. The RP is low cost for a FF body but the Z50 undercuts that by a not insignificant margin considering many will regard these as stepping stones towards the more expensive bodies. Many bought rebels with a cheap 70-300 zoom as a stepping stone towards eventually getting a 5D, 7D or 1D series camera with a 400mm tele, there's no reason to think this will be different in the world of mirrorless cameras.