I think this glosses over an important point. Hiring or firing is expensive in opportunity cost (e.g. project delays, disruption to the work environment, morale) and so it makes sense to internalize that cost in a hiring decision. Suppose Person A will provide value Y per year, cost X per year, and turn over in one year costing Z. Person B produces value Y - K, costs X, but will stay for 3. If K < (Z - Z/3) all else equal you'd choose person B. Building a brand that you jump ship for better jobs ought to cost you something, even if that something is much less than the salary you gain not being a gold-watch girl.