I don't understand why the developer wants to go back to his job. He must be making about $30.000 a month from this game right now. Maybe even more. So it shouldn't be about money, right? He probably loves firefighting and wants to do it because it's in his heart or something. Otherwise I couldn't make sense of it.
Because you don't know the exact numbers and this game (like any other) is made by more than just 1 man but a team of people who also get paid.
If you think that making 2500 renders in few months time and not 1 year is cheap or easy - you're wildly mistaken. (this and having VO costs good amount of cash)
Unlike some other games made by greedy people who want to pocket as much as possible doing as less as possible this game is involved with a lot of people who are getting paid for the work they do so this game is as good as it is and always on schedule.
You people need to stop trying to calculate who makes how much from games here and focus on playing the game and supporting the devs team when you can so they can continue delivering what everyone wants - quality and on schedule updates.