A team with nothing but superstars would be bankrupt by now.
It is only logical that a team like that could only lose money not earn. Quality limit is supposed to make the game more competitive.
And of course if you got a team full of 8~9* you always lose money. You are bypassing the limits of the quality you can field by spending tokens, which your opponents could also do.
So at the highest level it is a money war between heavy spenders. For a slight advantage in quality, the amount of token you need to spend is exponential. It all boil down to how desperate you are wanting to win.
Instead with a team of players 4* average you should be earning money if you adjust the ticket price properly. Even with only league and one friendly a day you should not be losing money.