If they can't do that then they just offshore it. The big tech firms are increasing their presence and offices in other countries for cheaper labor.
They've been offshoring as much as they can for decades. The H1-B program hasn't stopped it and if it were eliminated there wouldn't be a huge surge in offshoring. Many companies have already hit the limit on offshoring and had to pull things back onshore.
Offshored workers don't compete with me for food, housing, education, etc.
You're competing with 2 billion Asians. We're never going back to the 1950s no matter now much people cry about it.
Then let them. If they want to offshore, let them have the associated pros and cons, and free up real estate that American workers can use to start competitors.