Edit: You can see visas per company here with average salary https://h1bdata.info/topcompanies.php You can make an opinion for yourself but suffice to say that the bulk of the jobs are in cheap outsourcing firms, not in tech companies. (cf. google 15k VS tata consulting 73k)
Abuse by firms such as infosys and “bodyshopping” are of course a problem as well, but Microsoft, google et al love these visas too.
A lot of people who work in very senior positions in this industry came here via an H1B, it’s not just low level positions.
There are 85000 H1s given every year, 65000 if you do not count US graduates. The visa eith extensions can last for 6 years. However, if you have applied for a green card, you can easily go twice as long, extending it bit at a time. Now not everyone who gets an H1 stays, but lets try to catch the high end of this and see what the numbers would be. 85000 a year X 12 years would be close to a million.
Now H1 also comes along with H4 which is a spouse visa and I do not know if they are allowed to work today, but there is/was a provision that spouse could work. Assume 10% spouses work, that's another 100K.
And this is before we start counting L1s which many "shops" use. People can classify them differently but from what I have seen, half of those could as well be H1 and the company used L1 because they did not have annual cap issue or some other benefit.
So that takes me to a count of 1.8 million. Assuming 1/3rd of them do not stay back and return to their country, my ballpark number would be in the range of 1.2 M.
You are right about the H1B1. They should give the visa to the person, not to the company, so that people could credible threaten the company to walk away for a different job somewhere else. That would do away with the slave mentality.