When people get old they don't have much in their life other than their family and work, and many workoholics have only their work, case in point Warren Buffet,

When people get old they don't have much in their life other than their family and work, and many workoholics have only their work, case in point Warren Buffet, that's not proof that they would rather not do anything else. Or would've lived their lives differently if they had the chance, and many of them might be too proud to admit it at this point considering that they will soon be gone. It's just that work is the only thing left that makes them feel useful, wanted, and provides some sense of purpose in their lives. They have been so busy in work they don't know what else to do... nor is their body and brain capable of doing much more than what it has done most of its life. Many rich business people completely quit business and instead do philanthropy, case in point Bill Gates... Zuck's role model? Facebook is not something positive in the lens of history. It's just a big money maker. Maybe it will still be relevant in 20 years, but eventually it will be seen for what it is... as if it's not already. And all that will be left is the money, of which Zuck has more than enough to do much more worthwhile things with his life. Like perhaps philanthropy. Maybe he can really solve some problems before he dies in 40-50 or so years. Of which maybe the 10-20 next ones will be his prime.