Canon has the EOS C70 that is more or less what you called a mirrorless design. Its just recording 4k and has a smaller sensor. So its not that canon isn't abl

Canon has the EOS C70 that is more or less what you called a mirrorless design. Its just recording 4k and has a smaller sensor. So its not that canon isn't able to come up with a camera like the Alpha 7S series. And the Alpha 7s is also not able to record in 8k.