One other comment about Sony and high end mirrorless vs Canon/Nikon is that the battle with micro AF adjustment and lens calibration is something that, to my mind, really, really holds back DSLRs to this day, and frustrates me. Even in optimal conditions with a perched bird and good light and center point autofocus, I am amazed that my 7DII cannot deliver 100% focus performance with any lens I've tried on it. Mirrorless cameras have their own issues but it seems to be trending that they are more or less catching and perhaps already overtaking SLRs on autofocus as we speak. I think it is highly probably that in 5 years mirrorless bodies will be outperforming SLRs even at the highest levels. The performance of the A7III and A9 tracking eyes and faces of subjects in motion is damned impressive.