Salary cap work in a close league, not open.
Have a proof of a not close-league that it was tryied and failed?
No you don't.
You are just throwing more VOID arguments to keep your case on.
From your POV, what will happen to BB when a salary-cap will be set? [And please stop with the "all will leave the game" argument, as it only state your fear at this game and nothing else]
The answer - a salary cap means that each division will have the same average salary up to a small alowed difference, or/and those who will go over the Luxury tax will pay the others, and by that will make all teams at the division more competitive (money-wise).
When the competiticion is not already known at the start of the season, upon money comparison, those divisions will be more competitive and BB-managing oriented (god sake, I said BB-managing, and this is supposed to be an eBay game for some of the users POV...).