The trouble is that it's an ever-decreasing circle - initially, a few walk leaving those remaining to pick up the slack. Eventually they get miffed and walk leaving even fewer working much harder, who, of course get miffed or burnt out fairly quickly and leave or get signed off.
The good news is that a certain very senior politician, at a speech at a recent charity dinner, stated that all we need to do is make the military much more like civilian businesses and make everyone in the military more productive! One wonders how? Does he mean we all need to drop more bombs or shoot more people? Perhaps he means that we should all work longer hours and spend less time on our personal lives. Yet our senior leadership still wonder why people are leaving!!