"Winning with" rather than "winning because of" implies that teams with "winning with" quarterbacks are winning because of some other facet of the game.
In addition, "winning with" QB's seems to mean that, although they are not the main reason a team is winning, they are not a detriment to winning.
I suppose the remaining QB's fall under the categories of "can't win with" or "loses because of".
All of these are obviously generalities.
Okay, so where is the "winning because of" elements of the Cowboys"? Keep in mind that the Cowboys offense was ranked higher than their defense in both categories of scoring and yardage.
Well, the Cowboys offense's best rankings came in the categories of rushing TD's, where they were ranked #2 in the league as well as fumbles lost, also #2 in the league.
When it comes to having the 2nd best scoring RB's in the league, Zeke scored more TD's than all other Cowboys backs, including the QB's, combined. Now he is gone.
When it comes to having the 2nd lowest total of fumbles lost in the league, it helps to neutralize the negative effects of Dak's INT's to the point that, when you look at the defensive ranking in both categories, the combination gives the Cowboys the #2 ranking in turnover margin. This means that, despite Dak's INT's the Cowboys have the 2nd most favorable outcome when it comes to all aspects of turnovers last season.
Finally, Dak's overall career stats indicate that last season was an anomaly when it comes to INT's. Since joining the league in 2016, 65 quarterbacks have thrown at least 500 passes in their careers. Among them, Dak is ranked #21 in lowest INT rate, better than Aaron Rodgers, Joe Burrow, Jalen Hurts, Russel Wilson, Kirk Cousins, Lamar Jackson and Deshaun Watson.
Interesting how half of the "win because of" quarterbacks have a higher INT rate since 2016 than Dak Prescott.