The above is a good example of where theory and reality don't jive. Just because something makes a limited sort of sense mathematically doesn't mean it's good business practice. The best computer consulting companies in the country tend to have relatively high retention rates relative to their peers, for example. With any employee initiative, be sure to learn how the employees view the initiative. Don't just assume your employees will look at things the same way you do.
Companies do have different views toward their employees.
On the one extreme are the more ruthless, bottom-line employers, who will replace workers like ball bearings. At the other extreme are employers who feel they are personally responsible for the livelihood of their employees. As long as the person is doing a good job, the employer expects to keep him indefinitely. Unfortunately, when a recession hits, many companies will not be able to retain all of their workers without endangering the business. The sad fact is that for many companies employees represent a buffer against bad times, expanding in good times and contracting in bad times, in the best interests of the company.