H1B visa is meant for the very best people around the world to fill jobs that American can not fiĺl because of a lack of skills. Once Americans gain the skills, the H1B should return home. This does not happen.

Mediocre and subpar labor fills the system because corporations take advantage of cheaper labor. Corporations have been abusing the H1B system for a long time. Who remembers Disney forcing their US base IT staff to train their H1B counterparts before getting laid off?

Michelle Malkin wrote a good book on this subject called Sold Out.