I found this on Quora
Don't forget that there is no promotion/relegation system in the U.S. either. It is impossible to be a capitalist in American sports because you can't work harder/better to earn your way from Division 3 to the Premiership championship. All U.S. big league sports teams are guaranteed to continue making big money in perpetuity.
American teams are socialist because the law in the U.S. allows them to be, though socialist is not quite the correct term. The term that is used in American economics is "trust", which is a group of firms in the same industry who collude to fix prices and destroy competition in order to maximize profits and maintain power. Trusts have been illegal in the U.S. since the 19th century (unlike in Europe where many industries have traditionally functioned as trusts, ironically). A trust allows a set of companies to monopolize (technically oligopolize) an industry, construct high barriers to entry, and collude with each other to maximize profits. This is how all American sports work. NFL teams share television revenue equally, making it impossible not to make money even if your team is horrible and nobody goes to the games. My hometown NFL team is the Detroit Lions and they have been as bad as any professional team over the past 50 years. They always make a profit (that's why the Fords own the team). College football teams equally share their profits from television rights and the large bowl game payouts (e.g., Alabama shared all their bowl earnings with the rest of the SEC). Leagues execs are in charge of changing the rules of the game every year in order to maximize profits for all teams. Owners meet every year to discuss how they can cooperate to make more money together. Football and basketball don't even pay for their own player development leagues-- that's handled by universities. There is no competition in the board room or on the field (we call this 'parity'-- it means that everyone is a winner).
Americans don't know that this is going on because the teams appear to pay a lot of money for their employees (athletes). They are forced to do this because these human beings are extreme genetic rarities who use the privilege of their super strength to leverage favorable terms from the trusts (every athlete is a business). Basic economics dictates that the fewer teams there are, the more valuable the extreme genetic rarities are, so player unions work to keep salary numbers high by limiting the number of teams. They rarely negotiate basic health of the players (concussions). For many years, the Lions played American football on a concrete field covered in thin, unpadded carpet (it looks sooo good on the TV).
Professional sports in the U.S. may be the least competitive sports in the world, but that's the way we like it. They've worked out economic models to maximize profit for everyone involved- owners and players. Because so few Americans watch European soccer that we don't know what its like to have teams that compete against each other. So the answer is: money.