Here where I live, there is a giant Intel plant, and roaming around all over during lunchtime are dusky folk chattering away in languages native to the Indian subcontinent. Good, friendly folk, to be sure, but people that should not be imported to do a job most any properly trained American can do. You can't tell me Intel isn't screwing Americans over to hire these much cheaper to employ people.
Big business in general is run for the bottom line, and cares nothing at all about such things as a duty to employ it's own countrymen here in America. If they can import someone from half way around the world and avoid paying expensive benefits and at a lower salary, they will do it in a flash if we the people continue to tolerate it. It's a symptom of globalism - they think no one should be bound by borders or the laws of any particular country if they don't like them.
This change is a good first step, and must continue. Further, laws should be passed to protect American workers, and then those laws must be strictly enforced. It the original intent and language of the law authorizing the H1B visas had been correctly enforced, we wouldn't have this problem, but the globalists don't want that, and when they are in power, they simple subvert the laws that they don't like, as they have here.
The final and most important piece of that puzzle is that the citizens of this country simply must vote to keep the globalists out of political power. That, fundamentally, is the most important and effective way to prevent this kind of abuse and to cure the problems already caused by those who do not respect the idea of the rule of law.