If you were to explain the costs of knowledge lost, of training, of taking a risk on a new unknown person, of relationships, there's no answer because it doesn't show up in any operating expense worksheet.
What you're supposed to do is find another job, and explain that you love this job so much, but the other offer is really good, can they come up close to it and you'll stay. Repeat this every few years or find a new job and move to it.
Before investing to employees I think it should revisit management practices and strategies, which starts in MBA and university.
Instead of teaching how to increase shareholder value in the short term, it should also teach how to increase value to the society in the long term as well (and focus on it highly) - not just say: if you win society wins kind of generic fluff.
Without changing management strategies everything becomes short term after a while
Problem is this is quite often a requirement for a public company, to maximize company value/profits above all else.
Also execs who are more right-wing are typically not interested in helping the larger society in general.
And there are very few large public companies with active enough investors to oust a CEO over this, and even fewer that have both active and activist investors that would be interested in such a thing.
> the CEO can't take actions that intentionally hurt the company
And who gets to define what "hurt" means?
You'd have to prove that the CEO knew that it would hurt the company and still did it or that it's so ridiculously negligent that any sane person should have known.