I see how your new scenario is possible. Primary+second assists on every goal with assists efficiently distributed between wingers. Either 70 assist winger is still responsible for the creation of more goals than either 50 goal center is, however
Actually they are not. Getting an assist does not mean that particular assist would have been essential for the team to score goals.
Quiz part two: next year the same team continues with the same amount of goals scored. Both centers get 50 goals each. Same wingers, but this time they got no assists at all. No-one in the team has any assists. Zero. Nada. But the team still wins. How it is possible?
And the final quiz
: next season both the centers are injured. No goals. No assists. No points. No wins.
Conclusion. The 50 goal scorers are great players and without them the team wouldn’t have gotten any goals or wins. The wingers might also be great players, but if they can’t score goals or have anyone with them who are able to score, it doesn’t matter how good passers they might be. No-one scores, thus no wins for the team.
Of course in reality things are not like this, but neither are 50+0 or 0+70 players... well, 0+70 might.