Only in California? In my brief stint on a framing crew in Orlando and then in Charleston, every last one of the workers except me were Brazilians, and the boss was an illegal Russian. I got $9 an hour picking up discarded scrap wood and other odd jobs. They got $12 or $15 depending on skill level.
In 1979 I did construction job site cleanup and ran errands sounds like I had the same job you had- no foreigners, no illegals at all. It was in Arizona so the illegals had not begun to take over even there yet. I was the oddity on that job, only woman working on the whole site- they were building 300 houses. I know Americans were doing those jobs, I ended up working into an office job- saw illegals begin to take jobs, the company I worked for would not hire them but others did. Made the bidding process totally unfair. One contractor cheating on labor takes the competition out of it. It all should have been stopped then.
I had many family members working agriculture jobs and construction jobs, one by one most of the jobs went to illegals. No one cared except the people doing those jobs. People say you are pretty sorry if an illegal can take your job- they don’t understand the cost savings to the employer. Employers think they can replace a legal worker with a couple illegals and still come out ahead. Some of the jobs were skilled, so quality suffered but no one seemed to care about that either. Try to find someone to build real custom cabinetry, do detailed wood work in high end homes. Try to find someone that understands working with high end imported floor tile than cannot just be slapped down on the floor. Truly skilled construction workers are a thing of the past.