First, it is stupid to think you can identify such people.
Second, much of the benefit of immigration is how the special combination of immigrant grit and American opportunity creates a special synergy in the next generation.
Third, most of the contribution from the country, the overwhelming majority of the contribution, comes not from the top 1000, but from the 50 million others. Plus eventually their children who across every generation and every ethnic group have shown extraordinary upward mobility.
It is a shame you and so many others are willing to overlook the facts and the analysis and choosing to advocate for policies that will greatly harm Americans.