Soybean There are two main ways that come to mind in terms of making money on PC.
1. Licence and ad money on many online games. True Valhalla makes a good living doing this, and has written a book on it.
2. Work hard on one 'AAA indie game'. Any successful indie game you see that's 2D and doesn't rely on multiplayer or some performance intensive concept not optimized in C2, could be made in C2.
In regards to the question as to whether Steam is open to C2 games - it's as open as it it to any other game.