Some employees don't want to go through this whole process switching a job, leading to few employers taking "unfair advantage" of these employees. They are not offered fair wage hikes or promotions as the employer knows they are stuck in the green card queue for years.
But the thing is nothing is stopping these employees from making a move to a high paying job. They are just lethargic and don't want to take a risk. Employees should not sacrifice their career goals for immigration issues. How I do know? Been there, seen that, did that. I am still waiting for my green card for the last 6 years and I expect to wait for at least another 6-8 years.
https://www.congress.gov/bill/115th-congress/house-bill/392 can change this. This bill has bi-partisan support and I hope it will be put for a vote.
Totally false understanding of the H1B visa program. H1B employees are not cheap labor, in fact full-time H1B employees are paid on-par or more than American citizens. Employers are required, by law, to file the prevailing wages during labor certification before filing H1B visa.
Employers hire full-time H1B visa holders for only one reason: they simply can't find the people. And the business would suffer if they wait to only hire citizens or green card holders. So they spend exorbitant amount of money for visa and attorney fees and wait for through the whole H1B transfer process. It's not because H1Bs are cheap!