It’s all about the markets, if company A hires a lot and the market thinks it’s a sign of growth it rewards it with demand for its shares, then company B looks at A and sees a hiring wave as the only material event that could have triggered A’s shares outperforming its own and decides… fuck it let’s signal to the market that we do are growing.

Then the market psychology changes and some CEO is the first to think that maybe this time the market would reward the opposite action, aka a layoff. It works… so the next one over goes and the rest of the dominos fall in the name of competing for institutional dollars within a zero-ish sum game