Coaches train fighters to be champs. They're not paying the coaches anything when they're making $4K/$4K on the regional circuits. Once they're experienced enough to actually pay their coaches, they're also experienced enough to train without coaches. But they never would have got there in the first place if the coaches asked for payment up front. Loyalty has to be a thing. Otherwise, gyms will have to start signing their newbie fighters to long term exclusive contracts in return for training like Thai gyms do. That's why you see so many Thai fighters with the last name of their gym. It would be like "Lyoto Americankickboxingacademy", or Jon "Bones" WinklejohnJackson, or Georges "Rush" St. Tristargymnasium.