Since a game typically doesn't have a first mover advantage nor suffer from a "time is of the essence" problem, and given your opportunity cost of income, you should consider outsourcing the development of your game to a cheaper labor market. With your technical know how, you can supervise your team to your liking, launch the game, and see how it goes. While you still might be unhappy at work, this will preserve more of your savings than quitting, and give you a more viable option to quit in the future.