For starters, CEO/GM are judged on far more than winning percentage. There is sustainability, financial stability, membership, sponsorship, facilities, fan engagement, game-day experience and a whole lot of other stuff I’ve not mentioned. It’s a whole-of-club role. Winning premierships is the goal of the club, but not the only responsibility of the CEO - would you say that Doust was a successful CEO because he won one in 2010?
Secondly, winning percentage alone is a narrow-minded view of coaching ability. Yes, it’s part of it and ultimately the end game, but since there are so many other aspects to running a team (and the fact that so many coaches stats congregate around the 50% mark) that it needs to be taken into context with many other factors, some of which aren’t black and white.
To cherry pick that one statistic in order to compare a coaches success to the work done by a general manager of football is just silliness. The closer comparison would be Millward, but even his role is far less than what Gould has responsibility over.