It's probably not as big of a difference when you get away from silicon valley which is a special case. And I think one major reason silicon valley salaries are

It's probably not as big of a difference when you get away from silicon valley which is a special case. And I think one major reason silicon valley salaries are so high because non-compete clauses are invalid, so people can jump to a competitor at a moments notice if they are offered more money. Another thing I've heard is that many European countries have rules on how to terminate an employee, and most states in the US you can just fire someone at any time for almost any reason, or no reason. So in the US a high salary is essentially a short term risk that can be removed immediately if the company hits a financial downturn. US employees know that there is no loyalty from the company, and in-turn are constantly looking for new positions that pay more.