If America wasn't the preminent market then Coolmore wouldn't be running George Washington and Henrythenavigator at 10F's just before retiring them to stud, any more than they had any racing reason to Duke of Marmalade on dirt. The European market isn't without money or influence certainly, but the big bucks are stateside, and they're increasingly buying 10F horses and as I understand it least, this is where the pressure's being applied.
It started about 15 years ago and has taken root since, which is why Leger winners are now seen as a negative and horses who might conceivably have won the race like Youmzain are deliberately routed away from it by their owners if Channon is to be believed (which does seem strange given that the bleedin' things still in training). It's another reason why the French are supposed to have gone down to 10.5F's at Chantilly