I have long felt that this is true of much of the western world. The conservatism of investors vs the US must be one of the biggest reasons for US advantage
Its the population density and tax regime. Usa has high enough population density to have real wealth pools and low enough taxes that those wealth pools can create new billionaires when they invest in good ideas. Europe could do it if they dropped their tax rates and crazy labour protections to get more dynamic, but i think the current rich there like that the system aborts new billionaires before they are born.