USA vs Euro Motocross (theories)

Sitting here watching the qualifying highlights from Qatar I was thinking about some things. This is not to write RV off because he will win some races and be in the title hunt I think. But I think the European riders and their bike setups are better overall on wider ranges of conditions.
As Americans we try to make all of our Motocross tracks the same. Adding sand to hard tracks, grooming sand tracks, and generally trying to recreate the most enjoyable riding conditions for riders, and spectators. You never hear of US riders saying they tested on hard pack to find a setup, then in deep sand, etc. They can basically find something that works on one type of track and change a couple clickers. Our riders and their bikes aren't taught to adapt, with their riding or bike setup.

On the contrary, European tracks seem to have a very wide range of terrain and conditions that would require different technique, a rider that can identify bike characteristics and relay that to mechanics, and testing in multiple conditions. You see them riding shitty hard pack tracks, sand, mud, loam. So I would imagine they set up the bikes to be more adapted to certain conditions, or even run completely different setups based on testing in a variety of conditions

Our guys may have the fastest raw speed on 1 type of track that we replicate over and over, but overall European motocross riders may be better, because they can ride equally as good on different terrain.