It's not just about money. World has changed. Normal working people in EU are easily changing their schools, jobs, countries, going to other EU members or even USA. Because they want to succeed. Why will young sportsman think different? He will go as soon as possible. Will he succeed? Nobody can predict that.
Just saying that the difference in money he could make in EL v NBA in the long term is very large. I don't know what will factor into his decisions.