One explanation is there is simply more money sloshing around in the US tech sector. Creating a startup and raising a few million dollars in VC is just a lot easier in the US than in NL, so a lot more companies are simply able to pay those salaries.
At the other end of the scale, the largest US companies are simply more efficient than NL companies. Just compare the revenue pr employee for the 10 largest NL companies to the revenue pr employee for the 10 largest US companies and you'll see a stark difference. More revenue pr employee means more money to pay salaries (very simply).
At the other end of the scale, the largest US companies are simply more efficient than NL companies. Just compare the revenue pr employee for the 10 largest NL companies to the revenue pr employee for the 10 largest US companies and you'll see a stark difference. More revenue pr employee means more money to pay salaries (very simply).