The USA still wins the most medals but China is going more into specialization, e.g. in diving they have collected a dozen or so gold medals (a full set). The USA has recently entered fencing and wrestling more strongly but these are still not disciplines where they can be 100% sure of gold, like China in diving or table tennis. In general, the USA, as a country, has big problems now, also financial ones and this is also reflected in sports. It`s not an authoritarian country that tried to cover up its internal problems by winning a lot of medals at the games, e.g. the USSR, the DDR, etc.