One name, fifty-three contributors
A quarterback can play the best game of his career and lose because a kick missed, or play poorly and win because the defence produced two short fields. Nobody disputes this in the moment. Then the season ends, the record is written down next to one player's name, and it gets used as evidence in arguments about who is better.
The position is the most important on the field, which is exactly why the shorthand feels reasonable. Important is not the same as decisive on every single afternoon, and the statistic makes no attempt to separate the two.
What the number really measures
Largely, it measures the organisation a player joined. A quarterback drafted into a stable roster with a good line and a coherent defence will accumulate wins; the same player drafted three picks later into a rebuild will accumulate losses and a reputation. Careers get defined by that difference, and it was decided on a night the player had no say in.
It also measures longevity, which is why the career leaderboards are a list of people who stayed healthy and employed. Those are real achievements. They are not the achievement the statistic is usually cited to prove.
Ask better questions instead
Does the offence get better or worse when he plays? What happens on the downs where the defence knows a pass is coming? How often does a possession end because of a decision he made rather than a decision made around him? None of these are hard to ask, and all of them survive a change of team.
I am not arguing that wins are meaningless — winning is the point of the exercise. I am arguing that attributing them to one player is a claim, not a measurement, and it should be made with the same care as any other claim. Arena's NFL positions guide sets out what the job actually involves.