I still think it's impossible to run two companies that both require so much attention, given their stage.<p>Yes Jobs had Apple and Pixar, and Musk has Tesla and SpaceX. But both Pixar and SpaceX don't really require day-to-day CEO attention, they follow long term plans (movies, rockets). That's really different from Square and Twitter, which are both, in their own ways, in a kind of trouble.<p>I'd love to be proven wrong though -- so good luck, Jack!