400 to 500 hours of working ??
LOL !!! Complete bullshit.
Even if we assume that an author works on a game 24/7, that would be 720 hours a month.
Well, I doubt that this guy, or any other game developer here works half this time. I will go with the hypothesis that work on games like these ones takes 2 hours a day max. It means, 60 hours a month.
I perfectly understand that this developer wanted to make some money, but I don't like the fact that he's making fake facts and thinks of his followers as idiots.
I think you heavily underestimate the time you need to make games. The author also didn't write 400 to 500 hours every month but in total.
And I can believe that he needed 400-500 in total for this game. With 2 hours a day / 60 a month you won't get very far and I'm quite sure that any game developer who released some games worked a lot more on their games.
That said, I'm sad to hear this game has been abandoned.
The author of this game also heavily underestimated the work needed to be done for a successful game. It is not like you just make a game, throw it out on patreon and somewhere else and you make a lot of money from it. You usually also need to spend a lot of time, and/or money on advertising, social network and stuff and the money you make from your game usually builds up slowly, very little at the beginning, but it can increase a lot if you don't give up and continue with good work for a longer time.