He's still building Twitter and Square. Jobs never stopped building Apple.
Building companies goes well beyond building apps.
This comes up frequently on HN and seems to polarize people. The more it polarizes people the more on the fence I seem to find myself. I have worked similar hours split between two companies for four years. At times it sucks and at times it's great. Everyone is different.
From what I have learned from others, exceptional results require exceptional work and passion. Working 16 hours days is how it works for Jack. Ben Hogan was reported to work with a similar ethic when he started his golf career and he's now known among many as the greatest ball striker ever.
To me that's admirable, to others it isn't. Both positions are acceptable.
Of course it does, but he isn't the only one doing it anymore, and I suspect has a team of people at each company that assists and supports throughout the day, which was likely not the case in the very early days of twitter.
The required mental focus and energy to get one thing "off the ground" - past bootstrapped startup phase - is considerably different from keeping something going - and even growing - once it's hit an operational level that twitter has. I won't profess to know both sides from direct experience, but can see that they're not in the same place they were operationally/financially as they were 4 years ago.
OT: I was probably downvoted by someone who considers Twitter and Facebook as "startups".
