I guess I count as a multiple entrepreneur at this point, and I'm absolutely sure: starting your own business does not make you superhuman any more than anyone else, and trying to put in a silly number of hours over an extended period will still make your work rubbish just like everyone else.

I would not be surprised if the entrepreneurial mindset exaggerated the effect mentioned in the article where people who put in crazy hours feel very productive as a result, though. Perhaps that's one of the differences from just being a geek working for someone else: if it's your business, you are not only the geek who thinks he's being super-productive by working too hard, you're also the manager who has to tell the geek to stop being foolish.