“Layoffs are a social contagion.” This quote is gold. From: https://news.stanford.edu/2022/12/05/explains-recent-tech-layoffs-worried/
What explains recent tech layoffs, and why should we be worried? | Stanford News

As layoffs in the tech sector mount, Stanford Graduate School of Business Professor Jeffrey Pfeffer is worried. Research – by him, and others – has shown that the stress layoffs create takes a devastating toll on behavioral and physical health and increases mortality and morbidity substantially. Layoffs literally kill people, he said.

Stanford News
@peterme Another reason. It's difficult to fire underperformers yet companies know when they get large, there are many. So industry wide layoffs provide a cover story to do layoffs. I know from 1st hand experience that one large Redmond tech company used to implement layoffs by requiring every small subgroup to put forth their "bottom 10%" and these would be the ones let go. This let the company avoid legal issues of just firing people and having to document perfectly defensible rational.