This has been going on for decades. My first job out of university was at a dotcom consultancy with over 90% of software engineers there on H1B visas. The company was not at all shy about the fact that they only hired citizens/permanent residents if they had no other choice. I was hired because I had experience with a particular obscure RTOS that they couldn't find anyone on a visa who could do the work on a project they already told a client we were experts in.
Our VP of Software Engineering (here on a visa himself) stood right next to my desk telling one of our programmers not to worry about his visa expiring because they'd post his job for 24 hours on the company website, accept resumes for one week, and then declare the job unfillable by local talent so he could get his visa renewed. This was in 2000 and this type of thing has been practiced openly and with no fear of there ever being any consequences for violating both the letter and spirit of the law regarding using labor visas.
These threads end up fire hosed with people claiming hiring visa holders over citizens and permanent residents doesn't happen nor does it push down wages. They know these are lies and have been lies for decades. But since there are no consequences, legally or socially, it continues to be the default behavior. This in turn warps local talent development as more and more kids see that there's little reason to go into a career field where the government and business openly collude to disadvantage locals in favor of visa labor.