Are all of the best specialists in the USA?

Question

For each area of medicine(for example, neurologist, cardiologist...)

Answer 1

Considering the influx of them from other countries, in that sense, you may be right. As a Korean vet that spends a good amount of time at my local VA hospital, it is hard for me to come into contact with an American (that has been here more than for 1 generation) Dr. However, that speaks quite well for the medical training in other countries.

Answer 2

No definitely not, there are great physicians all over the world.  I am USA born and bred and proud of it, but we do not have a corner on the market of creativity and intelligence.