The cost to replace a good employee is shockingly high. Organizations that don't fight to keep their good people are chasing short term gains at the expense of their medium and long term. It is why many businesses can't figure out why they can't grow and think they are a great place to work because they offer bottom of their industry pay (which can be enticing for folks looking to break in, get experience, etc.)

For a lone manager, chasing short term gains at the expense of longer term might be the most rational strategy for their own careers.

Agreed. I would then want to understand the overall organizational structure that puts "line managers" in these situations. It is almost always some sort of organizational defect or lack of managerial skill that causes an employee to "save up" all their grievances to the point where they feel the only way to get what they want is through essentially dropping a bomb on their manager.

Managers are paid to look after the bottom line. The good ones do their best to balance that with treating their people well and fostering loyalty, but no balancing act ever goes entirely smoothly -- yet that's the one they're paid to perform. Businesses aren't charities or good-will missions.

You're right that businesses presently are not charities or good-will missions, but perhaps they should be. The way most businesses are currently run (ie, as profit mills chasing growth at any cost) is detrimental to the environment, society, and the economy itself. Business for its own sake is stupid AF.

I would not necessarily dispute any of that, but it does contravene the assumptions from which the owners of most businesses are proceeding, not to mention their investors, shareholders and board members. :-)

Why not go and start your ideal business then?

I understand, and as a development manager who needs to hire and retain technical employees i'd rather make the case to pay an extra 10-20k a year for a well-performing employee rather both risk losing someone for an intermittent or extended amount of time (clear value lost) and than spend time retraining someone (more value lost). All of which lowers productivity and hits the bottom line. Also takes a hit on team morale.

It could also be an opportunity to add valuable responsibilities to the employees role to justify the increase in wages, if thats applicable to the situation. Win-win for everyone.