it has to do with economics,most european chicks
come from eastern europe,which has a plethora of poor
white and thin,girls who are poor because these countries dont
have strong safety net and welfare programs like western europe.
In America we have a stronger economy,so girls dont have to fuck for food and rent just for prada bags.

also its culture sex is not as stigmatized in europe,being a pornstar,there is the equivalent of being kim kardashian or a stripper in america,so the cost benefeit is alot better for european chicks which why even in countries with a decent standard of living like the U.K,they stilll have hotter chicks in their movies compared to america.