No, in fact there are supposed to be safeguards in place to prevent this. The ostensible idea behind H1Bs is that the employer literally cannot, for any price,

No, in fact there are supposed to be safeguards in place to prevent this. The ostensible idea behind H1Bs is that the employer literally cannot, for any price, find the talent they need locally. They MUST hire foreign workers to come in and do the job. And the law is written such that the foreign workers--the ones who are there to do a job that no local person can do--get paid what an american worker would be paid to do the same job. That's to prevent the exact scenario you mentioned: a company hires cheap foreign labor under the H1B program, displacing qualified local labor. Of course it's all toothless bullshit, so that's exactly how it works, in practice.