The factory work doesn't pay as much as Nursing careers or Building Houses for carpenters, plumbers, roofers, etc. I have a feeling factories will use H1B Visa

The factory work doesn't pay as much as Nursing careers or Building Houses for carpenters, plumbers, roofers, etc. I have a feeling factories will use H1B Visas to bring in immigrants to do the work and fire them as soon as the H1B Visa expires, and hire all new H1B Visa workers.