The fact that a game with this level of greed exists and yet the dev behind it is making this much.
Proves that there is in fact a demand of Dota 2 adult games. The reason why the dev is making that much is because he/she is monopolizing the entirety of Dota 2 Porn gamespace. Should you, reading this post, a potential dev, please take note that if you were to create something of a game that of an equal quality with a less egregious monetization plan, you will literally claim half if not most of this creator's patrons and make way more than he does. I'd if I don't have a day job as a software engineer because the money's already there, just need to work to claim it.