A lot of CEOs get asked why they don't just retire, they don't...

A lot of CEOs get asked why they don't just retire, they don't need the money. And political leaders get asked why they don't give it away after a while and avoid all the stress. The answer is invariably what would I do that could be better than this. SI runs an international business in an incredibly exciting part of a dynamic industry, and is developing science that may change the way millions of people are treated for disease in the future. What's he going to do? Play golf three times a week and build model airplanes (no offence if that's your thing)? No, this is personal and he is already living his dream. He's not selling out. Eventually he will step down at a time of his choosing, an extremely wealthy man, but that's a long time away.