The article shows how high costs of replacing workers can lead to higher wages for current employees. When it's expensive to hire new workers, existing employees can demand higher pay. This higher pay can make them work harder and be more productive. As a result, the costs of replacing them with cheaper, less productive workers go up even more. This cycle continues, with higher wages leading to higher productivity, and vice versa. In this way, the link between effort and wages can make turnover costs have a bigger impact on wages.