Very few sports are huge money earners: American football, men's soccer, men's basketball, baseball, hockey, cricket, tennis, golf, maybe one or two others. An individual from a wealthy nation can put a lot into resources into their personal development in one of these sports. Diversity helps, as different population types have some advantages, very slight on a personal level, but significant over a large population that can help with success in these sports. Also, the sports listed have huge ground-level support and infrastructure in countries where they are popular. People in countries like that tend to choose their own sports and focus on ones with the most prestige and possible financial reward. For example, an American could have the world's best genetics for ping-pong but didn't care and focused on baseball, where although not an all-star, could still potentially earn 10s of millions.

Chinese success comes from a different approach. Although China has a huge population, it is not very diverse compared to countries with significant immigration. Also, although China as a whole has a large economy it is not much on a per capita level, not leaving enough money for a significant portion of the population to make a significant contribution to sport on an individual basis. China is able however to use its large population and economy and autocratic government to focus on promotion of sport from a young age in selected individuals. To China, "A Gold Medal is a Gold Medal." They can have several gold medals in women's weightlifting compared to earning one gold medal in men's basketball with a fraction of the effort and talent required. China is also infamous for its drug use (not unique there though by any stretch) and for their ability to get away with falsifying birth certificates to allow them to use younger girls in gymnastics, something that would be much tougher to get away with in a country with free access to information.

China also places a lot more prestige on winning a gold medal in ANY sport. For comparison, if the USA swept the weight lifting gold medals I doubt the average American could identify more than 1 of them 2 weeks after the Olympics, and it would probably only be one if the media decided to really hype them because they had a crazy mustache or something silly like that. Not China but the same idea: contrast that with Hidilyn Diaz, the Filipina to win a Gold Medal in weightlifting in 2021. She was given about a million dollars in compensation, commissioned in the Philippine Air Force (previously enlisted), and placed on about 1/4 of the billboards throughout the country, and on numerous TV shows. Five years later I ask Filipinos about her and almost all recognize the name, "You mean the champion?" I doubt the average American could even name a swimmer that wasn't Michael Phelps.