The problem with pro/rel is if $$$ isnt behind player development ie lower level clubs aren't compensated for pushing up talent to higher levels. The next best thing is the pay to play system and pay to play hates pro/rel because they want the money and a gated system guarantees that money doesnt go to players. Without the crazy amount of $$$ players can potentially make Soccer via Acadamies + pro/rel the sport will never become as popular as other sports in America.It's called promotion and relegation. We are trying to fix a problem in US youth soccer that we created. Gate keepers will come up with all kinds of reasons why promotion and relegation won't work; because it won't work for the status quo, those clubs will blow up, which is the solution.
Not to point out the gambling perspective but what makes soccer fun to bet on is that clubs are going all in players and development. Money clarifies better than anything else who is the best.