That's what people said about age 65. And then look what happened, only a handful of pilots left the majors each year between 2008 and 2013. My guess with age 68 most pilots will try to hang on for three more years, some will medical out a few will just be ready to retire, but the majority will hold on and get special issuance medicals if they need to. Why leave when you're at the top of the pay-scale and seniority, flying the plane and the routes you want???