The salaries of H-1B applications are public information. Here's Facebook's: <a href="https://h1bdata.info/index.php?em=Facebook+Inc&job=&city=&year=2019" rel="nofollow">https://h1bdata.info/index.php?em=Facebook+Inc&job=&city=&ye...</a><p>While the work visa structure does give the employee less leverage, and I've known several people that needed to get new employers quickly to stay in the country and this probably does limit the ability of people staying on work visas to shop around and make companies outbid each other for their labor. That said I am very dubious of calling this "modernized slavery". Sort by salary, ascending, and you can see that the significant majority (over 90%) make $100k or more, and most of those under 6 figure salaries are not in the Bay Area.
I've paid my dues in the industry very similar to tech lead, including my wife having to preemptively and defensively flee the country with our kids --