The post-retirement track record for your hyper-competitive, multiple-champion GOAT-class athletes is not necessarily one you'd want for yourself. So often they seem stranded, often surrounded but generally quite alone, peering down from atop a mile-high butte of money and notoriety at a world that is much too far away to recognize; the people moving through and within it, to the extent they are visible at all, have a busy and eminently squashab…