I see evidence of a collusion. My friends at several tech companies (software and hardware) received very similar sounding emails in similar time frame. I think the goal was "salary compression". Management was terrified of the turnover and salary growth so they decided to act. They threw a bunch of people on the labor market at once to cool it down. It would normalize eventually but you don't need long. Fired H1-B holders have to find a new job within 2 months or self deport.