With yesterday's announcement of the new lens mount to go on the new EOS R. That is a lot of expensive glass to go on basicly a mirrorless 6D. So when is Cannon going to roll out new 5D and 1D bodies to support these new lenses?
Some time before or after they end their product cycles, which is about 4 years, give or take, so maybe in 2020. One of them may get a hybrid viewfinder.
The EOS R has just started a system and will not kill the EF system but it will be expanded, only they now how and when.