Not all that are leaving are even going to flying jobs. There are more than one or two that are retiring from aviation, but not from working life. It always pays to keep your interests diversified and options open.
Also two FO's (that I know of) that quit with nothing to go back to. Anecdotal, yes, but was interesting to me that NO job was preferable to staying. Of course, most don't have that option, with family/kids/mortgage, (which EK exploits), hence probably why - presumably - younger joiners.