If the FF ILC market shrinks, like Canon believes it will, then having two camera lines which mostly replicate the capacities of the other makes no economic sense. So, bringing mirrorless cameras to market to replace mirrored cameras makes great sense. Replace and retire. Support the obsolete line, do not replace it with same kind technology.
Expect this trend to continue with the M- and R-lines replacing their respective mirrored counterparts. The replacement rate may be faster than first expected given the rate the market contracts.