Why was it in the headhunter’s interest to place a foreign worker? He gets paid less, if the person he places makes less money. But most headhunters would just want to place someone as soon as possible anyway.
Usually the charade works like this. The company ALREADY has a green card type waiting in the wings. The head hunter puts in a good show/front that they tried to find someone qualified. The requirements posted are usually ridiculous. When the mandatory amount of time has elapsed then suddenly this green card resume appears on the recruiters radar.
It is a scam and a game to short change US IT workers.