If there was a salary cap, then any surplus income that can’t be paid to the team would be kept by the board members. Currently the money goes to the players. As the players are the ones generating the income and creating the value, the majority of people are pleased with them profiting from their labour.
As a footnote, leagues without promotion and relegation are not seen by many (association) football fans as equitable.
That’s really interesting, I never would have thought that public infrastructure would be funded by privately owned sports teams.