> That’s the cynical approach, but most companies don’t actually want to lose valuable employees.

While an abstract rational actor like a company might come to this conclusion, day to day line managers often do not come to the same conclusions. A low performing employee affected by personal issues is dead weight on said line manager's budget and headcount, and therefore their metrics and their own performance and promotion. The trickle-down performance model often doesn't incentivize long-term-focused management practices.