Nonsense. Job applicants at the H1B level are all highly competitive, well-educated specialists of some sort.

You can't hire scab helicopter blade design engineers. Not even from abroad. You have a small pool of those who qualify looking for work (or actively keeping their ears alert for new work), muddied by many people tangentially quasi-qualified who want a job.

After you filter (imprecisely, but as well as you can), the pool is small, and you don't have enough qualified applicants to routinely work one group against another.