That might be true but hes not doing this alone. Hes the one making the decisions and the strategy but Square has >100 employees and Twitter has like what ? 600 ? This would be true if a big percentage of all the employees would be putting in these kind of hours, but i highly doubt thats the case. Also it doesnt factor in luck, which is a big part of startup success. Could Jack have pulled off Square as a nobody without the help of twitter ? I guess not. You could have started a Square Competitor at the same time as him, working even harder with all your people and even if you had the better product, you most probably wouldnt have won.