China has a bigger population, but this is more than offset by the huge US advantage in GENETIC DIVERSITY! It is a well known fact that West Africans dominate sprinting, East Africans dominate middle- and long-distance events, Eastern European whites dominate strength events, whites (in a more general sense) dominate swimming, and East Asians dominate in events that require hand-eye co-ordination, reaction speed and body control. China is genetically monotonous - 93% of its population are Han Chinese. Short of China adopting mass immigration (unlikely since they already have 1.3 billion
people), they (the Chinese) can only choose from one group. The US has a full deck to choose from. For that reason, the genetic advantage goes to the US, not China's huge population, as many people assume.

Team GB, as the host nation, has more athletes than any other country on this database: 557 registered (which is a few more than the official list published here), followed by the US (534), Russia (441), Australia (414), Germany (395). China has 379. Some 5% of all the athletes at the games are part of Team GB.

More athletes competing in the Olympic means more opportunities to win, in case your best athlete has a bad day.








One example
Track & field (athletics) way more than 60 medals up for grabs each olympics (US grabbed 29 so far )willing to bet over half or more of the medal winners are black. Black individuals representing China? not happening.


Tl:dr USA genetic diversity advantage plays a critical role in why Swimming and Track and field (probably the 2 events with most medals available will almost always put USA ahead. .