Correct, but most of us have at least 1 friend/relative who joined Hatzolah (for the lights & sirens /action) and dropped out after 2-5 years, realizing that not everyday it’s action & not everyday you get to save someone’s life
Or maybe they dropped out because it is very demanding? Leaving countless shabbos seudos, sedorim, davening, family time, etc. Training, keeping cars and equipment in perfect shape, having neighbors die in ur hands, etc. It all is time consuming, takes away from other obligations, emotional and so on. Life situations change and people can't always keep it going.