replace "are" with "were" and you are perhaps closer to the truth...otherwise you are just living in the past
"Why are americans the best?" Was the best. Things are changing. Anyway all of those fighters barely had any real opponents from outside the United States to even compete against. Of course accept from Duran fighting Leonard. Atari use to be the best video game system- things change.
Theyre not always the best, there have been dominant era's yes that is true...but they are simply just always viewed as the best in comparison to foreign fighters....i.e Lacy will destroy Calzaghe
Let me you something. Boxing throughout most of those fighters eras was solely an American sport. It is like the Denver Broncos winning the Super Bowl. Every single team was American, nearly every player is American- Americans had no choice but to win. People outside of America don't care about the NFL. Boxing is catching popularity outside of the United States now, and it is now showing results in success of foreign fighters. That, and oppurtunity that wasn't allowed for Eastern European fighters until 1991.
We have so many good fighters because we have so many people. America's population is over 300 million! I am not sure of this, but I believe we are the third (though possibly the 4th) largest population on the planet. China and India are one and two. China has produced some good boxers, but I don't think the sport is as popular there. I don't know of many Indian boxers, so I doubt it is very popular there. It is simple statistics. The more people you have, the higher chances you have of producing someone special.
Ask Emilianenko, or Vitaly... bring on any American you can find and we can settle this in MMA or Boxing whichever. :hey