It in essence is what is allowed in International Olympics so the model works. What it does not do is enforce shamateurism that implicitly favored wealthy elites as the only competitors:
"WHEN BARON PIERRE DE COUBERTIN had the idea of reviving the Olympic games of ancient Greece, he envisaged a strictly amateur affair. The Frenchman was deeply influenced by British attitudes to sport, or at least those of the British upper classes. These saw athletic pursuit in classical terms. That meant noble amateurism, underpinned by values such as fair play, stoicism and self-improvement for self-improvement's sake (all infused, no doubt, with a snobbish disdain for working-class professional footballers, cricketers and the like). De Coubertin thought this attitude, drummed into the ruling class in Britain's posh boarding schools, was the pillar on which its empire was built. He wanted his Olympic games to spread that ideal.
The early modern gamesthe first of which were held in Athens in 1896reflected this. The rules stated that participants must never have competed for money nor, indeed, ever would. Jim Thorpe, one of America's most famous athletes at the time, was stripped of his decathlon and pentathlon gold medals, won in 1912 in Stockholm, after it was discovered he had been paid (a pittance) for playing semi-professional baseball while he was in college. Yet from the start, as Matthew Llewellyn and John Gleaves describe in their book, "The Rise and Fall of Olympic Amateurism", the Olympic committee was accused of hypocrisy. Some of the early games, such as in Paris in 1900, were attached to world trade fairs, shrines to capitalism not classicism. And the winners in some of the more aristocratic sports, including automobile racing, equestrianism and motor-boat racing, were in fact awarded prizes of money or objets d'art. What is more, the Olympics aimed to be open to all and judged on ability. But amateurism meant that the games were open only to those of independent wealth."
https://www.economist.com/the-economist-explains/2021/07/20/why-did-the-olympics-ditch-their-amateur-athlete-requirement"In the 1940s and '50s, the tennis stars of the world found their gold only on trophy figurines and engraved bowls. Jack Kramer was one of those tennis stars then, and he had a plan to change that.
Seventy-five years ago, in the summer of 1947, he began his plan by winning the men's singles title at Wimbledon. He beat a Bay Area player named Tom Brown, 6-1, 6-3, 6-2. Brown, later a prominent lawyer, was known as "The San Francisco Flailer." Little successful flailing in this one. The match took 45 minutes.
Kramer got a nice trophy, back then called the Renshaw Cup, which eventually found its resting place inside the front door of the Kramer residence at 231 Glenroy Place in Bel Air. There, it was used as a convenient drop-off spot for whomever had gone out to the mailbox that day. He also got a nice trophy later that summer of '47, when he won the U.S. Nationals at Forest Hills. His plan, to win two majors and establish his star power before turning pro, nearly came crashing down in that one. He lost the first two sets of a five-setter to Frankie Parker and memorialized that moment for years.
"I looked into the stands, where my money guy was," he said, "and all I saw was the top of his head. He was bent down, fearing the worst."
The worst would have been Kramer losing, which he did not. His comeback victory, paired with doubles titles at both 1947 Wimbledon and the U.S. Nationals a feat achieved in the same summer only by him, Don Budge and John McEnroe was the beginning of the end of tennis "shamateurism," as Kramer called it."
https://www.latimes.com/sports/story/2022-06-27/wimbledon-legend-jack-kramer-started-tennis-pro-movement