This is commonly stated but is not true. US companies are required to pay the "Prevailing Wage" [0] to H-1Bs, so they cannot use foreigners to undercut US citizens.
However, foreigners whose presence in the US is dependent on their employment are certainly more likely to be abused by employers
This is laughable. I do not know how the government calculates those wages, but as someone who got to US on H-1B visa this year I'm making more than 2x the "prevailing wage" listed on my LCA application.
Just to clarify: my job is a Software Architect, in one of East Coast states, and the prevailing wage listed in my application was $84k. So it is not that my salary is especially good, it's this government-mandated one that is a joke.
I'm lucky, because I came here to work for the same company I used to work in my home country so I got offered good terms (somehow H-1B was easier to get than L-1). If some company offered me a job for the "prevailing wage" I would laugh in their face, but I'm sure for some people that would seem like a lucrative offer.
I know from talking to my American colleagues that my total comp is around the same level as theirs, so at least at my company they don't undercut US citizens.
Your listed PW does seem quite low, and I don't know how they actually measure it. I certainly agree that companies will do whatever they can to lower wages for all worker, and not including stock or bonus in the prevailing wage is ripe for abuse. Perhaps some reform for this law is in order.