Milky
The problem with US rider's is that the more electronics came into play, the less sliding...
Americans where used to train in flat tracks and that's why American rider's dominated the earlier GP Championships, on the 70's - 80's big jap elastic racing machines were always sideways... Roberts, Spencer, Lawson. In the 90's stiffer chassis and powervalves allowed better control but still the rear wheel wanted to pass the front... Mamola, Rainey, Schwantz, Cocinsky, then Roberts Jr. and finally Hayden gave us a taste of American macho riding.
Don't forget the Aussies that also trained in similkar conditions and therefore also had/have the upper hand when sliding with a lot of horsepower (Magee, Gardner, Beattie, Doohan, Stoner) because they also "grew up" in similar conditions...
The last brutal bikes to ride where the 500s, any rider capable of winning with that thing also mastered sliding but early electronics also meant the a more "European" style started to work...
The beginning of the 4 strokes era also brought more electronics, grip improved and the most important factor became corner speed... and then only very special riders managed to find the balance beetwen the 2 worlds: Vale, (Hayden), Stoner Pedrosa and Lorenzo. The aliens. The rest super riders but missing a little bit of magic...
Now, it is all about the "cantera", young guns. Now the riders are elite athletes, the outcome depends on the smallest of the details and the preparations. That's why MotoGP will be Spanish - Italian territory for the next years. Because we invested more resources than anybody else.