I think we've lost out on a few billion dollar startups and awesome inventions by locking people to the H1-B job they got hired for.
All H1B holders are more than eager to become citizens and currently there is already a pathway defined but the system is a nightmare.
Especially countries like India which are enormously backlogged.
No, H-1B visas are explicitly nonimmigrant visas for temporary workers. [1]
> They terminate in greencards after one renewal
No, they don't. You can apply for a GC, but there's nothing automatic about the process, and the GC is not guaranteed to be approved either.
[1] https://www.uscis.gov/working-united-states/temporary-worker...
The greencard process is a multi step, often many year process. If you are from a country with per country limits you can be approved for a green card, which will allow your H1B to be renewed indefinitely, but you still have the alien conditions including needing to maintain the same/similar employment.
H1-B is one of the main ways people get a green card and citizenship since you can have immigrant intent on H1-B, something you can't on a lot of other visas.
Or am I misunderstanding your first statement?
Fair is fair.
The economic impact of immigrants is not under debate, however your examples are poor choices as I don't think any of those people came to the US on an H1B visa. If anything it's an argument against H1B.