I agree.Why do you assume the R and RF line is more profitable? You are equating profits with cost, but they aren't the same. The R and RF lines are more expensive, but the profit margins on the EF line are likely much higher since all the development and embedded costs have long since been paid for.
The RP and R are much cheaper than the latest 6D and 5D.
I assume that new versions of those cameras would cost about the same as R6 and R5.