Canon Rumors reports on chatter about an R7 (7D sort of use case), R8 (vloggers), R9 (entry level) set of crop-sensor-equipped cameras. Release dates would be anticipated around end of this year or first quarter of next. This would spell the violent discontinuation of the M series of crop cameras.
Countervailing this: patent activity regarding crop sensor lens development has been anemic to non-existent; the sort of level of research that would be expected if Canon were to limit crop sensor use to security and industrial cameras.