This reminds me of the new game Andrew Gower and his brothers have been working on, Brighter Shores. It's a pure passion project based on a from scratch game engine that was created to make programming (even massively) multiplayer online games much easier.

The goal isn't profit but rather, to have fun, and make a cool enjoyable game. He's said they've made more than enough money from the sale of Jagex and RuneScape back in the day (which FWIW, he regrets that sale and a lot of what has happened at Jagex/to RuneScape).

I love to see game developers (and people in general that ... "make it" and then go "you know what, I do have enough").