I used to work as a desktop support/network engineer for a large Wall Street brokerage firm. When downsizing occurred during the 2002 recession, the company used that opportunity to release American workers, while retaining foreign workers on the H-1B visa program. When I left, the bulk of engineers remaining were foreigners, which provided the company with cheap, easy to exploit labor.
Qualified American engineers need not apply.
I'll go you one better....the Fortune 500 firm I work for now had a significant downsizing effort over five years that made no apologies for releasing over 10,000 domestic employees. In fact, while the layoffs were hitting every day, job descriptions and paper-titles were being changed to accommodate the "new" workforce of H1B's. It was all completely legal and I'm sure we're saving a ton on payroll.
I'm still here, but the last time I worked a project with another "domestic" employee was many years ago. I call all the H1B's "Corky" just to have a laugh at their expense. My number could be up any day.