Are you sure about that?
Microsoft recently laid off 9,000 American workers while applying for 14,000 H1B visa workers [0]. They are transparently offshoring jobs from Americans to foreign workers.
[0] https://www.msn.com/en-us/money/markets/microsoft-applied-to...
But where are the job listings that h1b applicants are using. It seems like job availability is just down overall