Could you ask them on what visa they moved to the U.S.? I know a few French people in New York. But they're on J-1 visas -- which are very short in duration (~1 year), and truly temporary -- you are required to have plans to return to your "home country" after that period. It offers no practical path towards permanent residence.

The only visas that don't prohibit immigrant intent (i.e. desire to immigrate + company applying for permanent residence for you) are the H-1B visa, L-1 visa, and O-1 visa. For anyone looking to permanently move the U.S. on the basis of skills, those are the only options. (I didn't mention the L-1 and O-1 in my comment above because they're even more narrowly granted.)

> only of of them is technically better

Technical skill doesn't really matter with the H-1B visa; only salary really does. Even going to a top university doesn't mean anything. The lottery doesn't discriminate.

There are foreign students who graduate from the best universities in the U.S. like Harvard, Yale, MIT, etc, often with advanced degrees (Master's / PhD), with good high-paying jobs, who get deported from the US because they did not win the H-1B lottery.

The Harvard Crimson complained about this even back in 2007: https://www.thecrimson.com/article/2007/4/9/raise-the-h-1b-c...