Yes, the NFL is an unregulated (if not legislated by the Sports Broadcasting Act of 1961) monopoly cartel. A cartel is a group of competing firms that collude to act as a monopoly (one seller) and monopsony (one buyer).  I have argued that it is a “natural cartel” because its product necessarily involves the joint production of a contest/game and any team is therefore only as strong as its weakest opponent.

Monopolies and cartels violate antitrust law because they damage the social welfare. Natural monopolies are allowed, if they are regulated, because their product is more efficiently produced by one firm. (utilities and media) The same regulation argument would apply to sports leagues as “natural cartels.”

https://my.vanderbilt.edu/vrooman/2018/03/league-of-ordinary-gentlemen/

Yes. Competitive markets are efficient because they convert individual greed (profit max motive) to “social harmony.” (Adam Smith’s invisible hand”). Monopolies are considered inefficient because the raw profit motive is unchecked and therefore it leads to suboptimal social welfare: higher profits for owners but higher prices for fans and fees networks and lower wages for players than would be available in competitive markets.

Greed and abuse are regulated by competition (or the threat of a rival league competition) and unbridled monopoly greed and profit seeking is unchecked for a monopoly.

See the attached graph for prima facie proof of monopoly power.

A closed monopoly league would not rationally duplicate any existing monopoly market because two monopolies are always more valuable than one duopoly market, regardless of market size. In contrast, competing rival leagues will expand into occupied markets because they don’t care about damaging the profits of the original team. That’s the efficiency power of competition and why currently existing dual markets are all remnants of rival league mergers in the past.

A notable exception can be found in the open leagues of European Football where the top leagues teams are composed of quality clubs promoted form lower tiers in the league pyramids. For example, there are six Premier League clubs located in greater London because the English Premiership is populated by a promotion-relegation process that rewards team quality over the specific interest of individual monopoly clubs.

The pro-rel scheme also limits the tanking epidemic that now plagues NA sports leagues. If a team tanks it is simply relegated. In theory a team can be progressively promoted from the bottom to the top of the open pyramid structure of European football.

https://my.vanderbilt.edu/vrooman/2017/09/2984/

https://my.vanderbilt.edu/vrooman/2016/01/triopoly-in-la/