Earlier quoted context omitted.
H1-B visas eventually expire. I think it’s technically a guest worker visa, so the expectation is that the visa holder will go back to their home country after working in the US a few years.
H1-B is an immigrant intent (actually dual intent) visa. I know a lot of Canadians that started working in the US on a TN visa, which doesn't let you ever become a permanent resident. They had to do all the paperwork (and win the lottery) to convert to H1-B status so they could begin the process of getting permanent residency.
The statutory protection for H1Bs is thin. In 1990, Congress excluded H1B from the requirement applicable to other non-immigrants that they retain a foreign residence, and from the rebuttal presumption that someone who applies for a green card has immigrant intent. That’s it. The common operation of H1B as being an immigrant-intent visa is mostly a matter of administrative grace.