What does the gym make money from?

Generally speaking, gyms rely on collecting initial membership fees: annual cards, season cards, monthly cards, etc. On average, the annual fee varies from 1000 to 3000 yuan according to the grade of the gym. However, the admission fee is not the only way to make money. The coach will recommend private classes to members, which is a considerable income, which generally varies from one class in 200 yuan. The other is to sell products: fitness protective gear, sportswear, protein powder and so on. This is the way to make money in the gym at present. I wonder if there are other ways to make money elsewhere.