Cannon and Nikon were always seen as the go to.
Sony (in part because they are now the biggest and best manufacturers of the CMOS detectors) were then seen to have taken a dramatic lead.
The Sony alpha range was then seen to be a dominant camera (especially with their mirrorless range).
The comment was that they keep their best CMOS chips for themselves, and the remainder for other camera manufacturers.
(Note that I am a bottom end mirrored SLR user. And was watching the progression of positive reviews move from Nicon and Cannon onto Sony. But have never had a chance to use a Sony).
SFK