The Gift That Keeps On Giving
What's the incentive for mass firings?
(1) Large short-term reduction in costs which usually increases stock price which attracts more investors and increases net worth of stock holders and makes personal profits if liquidated.
(2) Any negative repercussions of the firings is usually short-lived. Morale plummets initially causing reduction in individual productivity (which is not perceived by management since the massive numerical increase in productivity caused solely by fewer people now responsible for doing more work dwarfs it). However, without more layoffs, the remaining workers lose their fear of "being next" after a few weeks. That's when a trickle of new hiring begins which is hyped extensively, internally and externally, to show the company's new found "strength". Over a year or so, monthly figures are released showing "new job creation". In short, the one-time massive layoff was largely to allow the company to show months of "growth".
(3) Undesirables can be purged without following disciplinary procedures.
(4) The company can call itself "lean and mean" which somehow is considered good nowadays despite the fact that, in nature, "lean and mean" would usually describe an animal that is starving and desperately attacking anything and everything they encounter.