How? Please tell us as we desperately need an answer. They just go and infect every company. It is still generally considered an achievement to get a business degree from an elite school in some circles so the pipeline is not going away either.
The "easiest" (ethical) way involves a societal change to what people (and therefore, stockholers) value. Other countries do not in fact like it when a CEO needs to layoff people, and ofc other countries have protections against frivolous firings. So doing that isn't just a legal issue but a financial pain point.
If the US ever had it, it needs to bring back shaming unethical business decisions. Layoffs should tank a company's share and poison the exec class in current and future endeavors, not give a tiny bump of shares and a golden parachute at best. But that's an uphill battle from what I see.
Guerilla efforts to make their lives as much of a living nightmare as their decisions make others' might be what's left. Non-violent, targeted harassment with clear qualification (at least X net worth, at least Y layoffs, in role at Z corp) as a form of civil disobedience. Hopefully just the threat would get the ball rolling on treating the less well-off with more dignity. If anyone thinks this is unethical, so is a $2,000 plate while people are dumpster diving out back.