Not close to that much left over, a lot of money is spent in USA, you're in a foreign country and you spend money on tourisy stuff, plus you're usually "alone" there, and spend more in bars, restaurants, etc.... many came home with very little left over (except a nice line in their CV).

You're paid good money here for 37.5 hours per week, for ~10 months per year, sure the net number is higher in US, but calculating what's left over per hour of work is not that much in favour of US, especially considering what you can buy with that. One of the friends who worked there (google in sf) spent over 80hours per week in office, something like that is not just unheard over here, but also illegal. He was basically working two jobs there while being paid for one.

And yes, of course at some point (when you earn enough to live comfortably) your priorities become free time and other things, but again, that means that the company needs to pay more, to get another person to split the work. That's why everyone who did that says that the experience was great but that it's not worth it, neither financially nor health-wise.