Samuel H
Major Contributor
It seems to me: they don't have yet an ASIC that can do either 4k-60fps or 10-bit within the thermal requirements of these mirrorless cameras. Which is surprising, given how everybody else and their dog is already doing it (well, at least Panasonic, Fuji, BM). But it does take a long time to develop a new ASIC (easily 2-4 years) so, who knows, maybe they failed to foresee how fast the market would move in these directions.