If you get fired or laid off, you only have 60 days to find a new job or be deported. Also depending on where you are in the green card process, you can lose your place.

This creates an incentive for H-1B workers to tolerate working conditions that American workers wouldn't.

Again, if you have terrible work conditions, you as an H1B have the same options as US citizens. You look for a different job and maybe suck it up for a couple of months, just like a US citizen would.

And while yes, if have an ongoing green card process which takes 12-18 months, you may have an incentive to stick around to see it to completion, anyone who has their I-140, does not actually “lose their place” in the green card process. They can file for a new I140 and retain their place in the queue by retaining the priority date from the previous application.

If you think US citizens don’t stick around for a bit in a shitty job for a variety of reasons, then you’d be lying. People (including US citizens) don’t just quit jobs whenever they want without a plan like you’re making it sound. At least not ones that carry a reasonable wage, health insurance and other benefits. Again, all with the caveat of me not talking about consulting firms, which obviously don’t exactly have the best workplace environments.