I think it's because the US tech companies have been far more successful in the the global technology industry than other countries which has led to higher prof

I think it's because the US tech companies have been far more successful in the the global technology industry than other countries which has led to higher profits which has led to increased salaries. Also in order to stay ahead of the rest of the world, the top tech companies aggressively poach the best engineers from companies all over the world, which leads to higher salaries as well.