America is the leading economy in the world today not because it has the most number of people, but because it has the best and the brightest.
We have the smartest people not because the smartest people of the world were all born here, but because smart people born elsewhere have been immigrating to the United States.
Stopping or reducing this inflow of talent is not the path to prosperity.
US tech exports in 2018 was $338 billion. Tech is our biggest export by far. Think of the US tech industry as a siphon that sucks in wealth from foreign countries. Would you want to make that siphon bigger or smaller?
If you want to make that siphon bigger — and more competitive — how would you do it? By limiting the people that can work in tech to whoever companies can hire locally, or by bringing in the smartest people from around the world?
Keep in mind that the money this siphon brings in is benefiting not just tech workers and tech shareholders. When the money is spent it turns the wheels of our economy, which leads to prosperity for all Americans, not just the 8% or so that work in tech.
The tech industry vacuums up money from foreign countries and pumps it into the economy of our country. The beneficiaries include all Americans, including those who work in restaurants, retail, healthcare, insurance, education, housing, transportation, entertainment and so on.
Limiting tech industry to whoever companies can hire locally will hurt its global competitiveness. Such a move will not just hurt the few would-be tech immigrants that are prevented from immigrating, but American prosperity in general.