Tony Northrup says Sony has probably a near two year “advantage” over the new Nikon and Canon FF mirrorless
Tony and Chelsea Northrup do believe than even if Nikon and Canon new FF mirrorless will be as good as the current A7-A9 line Sony is sill nearly two years ahead of them. The Sony A9 is 18 months old. At the time Canon and Nikon FF mirrorless will be available on the market Sony will be already close to a new Sony A9II launch.
P.S.: And they didn’t take into considertaion the already large Sony FE lens system :)