Eventually all Canon and Nikon cameras will be Mirrorless, the only question is when.
Probably premature to debate too much but the signs are that Canon don't have a higher end mirrorless immanent. Nikon don;t either, but their CEO has openly spoken about the existence of a higher end model,. More so, if you look at the Z6/7 they have been purposely crippled, and I don't mean the 1 card slot. The buffers are incredibly small, this could have been made the same as the D850 without increasing the size. They designed a new battery type, but kept a small capacity.