As my BB colleagues say, there can be two caps, a hard cap and one with exceptions where trainable players would enter.
We could add a luxury tax.
Another factor that could be added to the Max cap and Min Cap is to make a League Ranking.
For example: Spain is the country with the most successful clubs in international competitions. Its Salary Cap would be $1,200,000 per month and therefore its box office income would also increase by the same % of the salary cap.
And if Venezuela is the country with the least successful clubs in international competitions, its Salary Cap would be $800,000 and also its box office income will not receive any type of Bonus.