If we get to field 50 teams we would even win more gold.

No you wouldn't.
You must be confusing high level competition sport and picking strawberries in a field.
The number of medals for one team doesn't depend of how many athletes you send, but of how many athletes with a chance to get a medal you send. This is particularly true for Gold medals.

France could send half as many athletes and still get about the same number of medals.
The US could send 10 times more athletes and still get about the same number of medals.

Again, this is not the point.
Whatever the EU is a country or not, whatever it's fair or not to add the medals of 27 individual countries, or split into 50 the medals of one county, whatever if most US medals usually come from 3 or 4 states, these are elements everybody know and should not prevent you from placing a bet.