> In practice, though, H1-B becomes indentured servitude, since they cannot freely move between companies.

Not true. An H1-B can change job. I did it a number of times without any problem. In addition, good companies do not take advantage of this so called immobility. Netflix certainly does not. Its CEO used to say money shouldn't be an issue to employees, and he certainly means it. In fact, Netflix's culture is so good to ICs, but I digressed.