[sinkwool]

Yeah, that was a very weird comparison. Not only do those countries send 6 people each, those four started participating in 1959 while US started in 1974 and China in 1985. Though arguably, those first olympiads featured fewer countries, (with presumably stronger competition) so they had to compete against each other for medals.

Another factor might be the number of distinct participants. I believe the Chinese enforce a one-participation limit, though I don't know if that would make it more or less likely to get gold.