https://en.wikipedia.org/wiki/Salary_cap
"In theory, there are two main benefits derived from salary caps – promotion of parity between teams, and control of costs.
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"Primarily, an effective salary cap prevents wealthy teams from certain destructive behaviours, such as signing a multitude of high-paid star players to prevent their rivals from accessing these players, and ensuring victory through superior economic power. With a salary cap, each club has roughly the same economic power to attract players, which contributes to parity by producing roughly equal playing talent in each team in the league, and in turn brings economic benefits to the league and to its individual teams.
"Leagues need to ensure a degree of parity between teams so that games are exciting for the fans and not a foregone conclusion. The leagues that have adopted salary caps generally do so because they believe letting richer teams accumulate talent affects the quality of the sporting product they want to sell. If only one or a handful of dominant teams are able to win consistently and challenge for the championship, many of the contests will be blowouts by the superior team, reducing the sport's attractiveness for fans at the stadium and viewers on television. Television revenue is an important part of the income of many sports around the world, and the more evenly matched and exciting the contests, the more interesting the television product, and the higher the value of the television broadcast rights. An unbalanced league also threatens the financial viability of the weaker teams, because if there is no long-term hope of their team winning, fans of the weaker clubs will gravitate to other sports and leagues."
How much fun would it be for you if you were in a small market and knew you could never sign the players necessary to play in a championship game?