Right. I started a comment picking at the Buffett example before seeing yours. Sure, he's been lucky to preserve his mental capacity into old age, but it's not

Right. I started a comment picking at the Buffett example before seeing yours. Sure, he's been lucky to preserve his mental capacity into old age, but it's not fair to dismiss his persistence. In particular, Berkshire has one of the few mega-cap business models that's actually possible to replicate on a small-scale: start/buy a cash-flowing business, use the earnings to invest in more, repeat. It's easier if you figure out negative cash conversion cycles before everyone else, but that part isn't necessary to apply the model.