He worked for roughly 40 of the 48 available hours. That’s a full work week in 2 days. You also won’t see him flipping between his editor and news or chat programs.
He’s working within a creative & technical domain he’s clearly mastered, using tools he completely knows, and is thus able to make incredible progress.
I’ve heard minecraft’s success ‘explained’ in so many ways, from luck to marketing genius to niche appeal. Watching notch code, I think it’s due more to a very competent, hardworking guy putting in an unbelievable number of hours. He just gets it done.
I can think back to many times where I used customer validation as an excuse for being lazy regarding product development. I’m sure there’s a middle ground, but I’m thinking more and more that lean startup is overly conservative in what it’s willing to build well. Sometimes you need to set a craftsman loose.