By law, an employer is required to pay H1-B at least as much or more than the US market average for the given position.

By law maybe, but it reality, far from it. Employers use foreign contractors to save money, not because they can't find someone in the US at the "market average" price, but because they can find a foreign worker and illegally pay them less.

That's another reason the smart ones may be leaving. They have priced themselves out of the market. The came over with dreams of making a nice "American" salary and are leaving disappointed. Companies want cheap labor.

Exactly - and another hypermiling technique that tremendously hurts everyone else is slow acceleration from red lights in heavy traffic. Someone near the front of the line should accelerate quickly in order to enable as many people as possible to get through the light. One person saving a few drops of gas can easily lead to many cars missing the green light and idling for another 2 minutes. In heavy traffic situations, people need to drive to optimize TRAFFIC efficiency, not their car's personal efficiency. Of course, this only applies in heavy traffic situations where people have to wait at the same light for multiple cycles.