Nope, it's not 100% required, there are exceptions for certain job categories like nursing and there's also the extraordinary ability exception.
(Not trying to be pedantic but US immigration law is full of random loopholes and people who qualify for them, or might be able to qualify with a bit of work, often aren't aware.)
Not sure if it’s still the case but extraordinary ability green cards used to be surprisingly easy to get for software engineers! Get your name on a patent (not as hard as you think, companies love adding to their IP portfolio), get accepted to do a couple of conference talks, and you’re most of the way there. Or so I was told a few years ago by someone trying this route.
