Thirty five years ago I saw a want ad for a pilot from a small flight school in west Texas. The job description required very specific flight time, something like 573 TT with 27 MEL. And fluent in Farsi. In order to sponsor an employee the employer must show there are no Americans who are qualified for the job. I figured they had an Iranian CFI they were trying to help keep in the country. They could post the ad, show they got no responses and then say a green card should be issued to their person who met the requirements.
For regular airline jobs, as long as pilots sign up for $2000 a month jobs there will be no need for foreign pilots.