Because over the last four decades or so, ever since Nixon and Kissinger handed over our economy to Chairman Mao in 1971, the amount of production that is truly "value added" has been shrinking in the US.
That is the sort of work where experience, knowledge, skills and a strong work ethic in your labor force is to be valued, in fact, is essential and like a piece of expensive machinery or any other high dollar investment in capital, should be treated with respect and properly cared for.
The new model of employment, where little, if anything, of value is actually produced, has little use for such outdated notions.
Labor and employees now are a sunk cost, overhead, no different than a light bill or cost of office supplies, to be cut and trimmed and squeezed back to the last penny.