The story of "it ruined my usual lifestyle" is something fishy for sure. Don't everybody want to change their lifestyles for the better? Since the guy made 50k/day, I assume there's something behind the curtains. Something should've went extremely wrong for the author to effectively kill his app.
Maybe, premature market testing, copyright problems, or a part of viral campaign. The latter one is something extremely unlikely to be true, I believe. You don't usually promote one of the most popular apps in such a weird way.
Yeah, the must be more to it. He probably had legal pressure from someone. If he was just fed up from the attention he could've just kept it up and running and just refused media attention etc and kept himself to himself.