As someone with a disabled older brother, video games have played a very special role in my life. In addition to it being one of the biggest ways for me to bond with my disabled brother, It also was a way for me to escape a sometimes harsh reality. I could completely immerse myself into a new world where I felt like I actually mattered.
You want to know how to really make money with video games?
Write an application that can monitor a game in progress. This way you could have single player games compete against each other.
For example,
Rimworld is a very popular game that many people want multiplayer on. It allows you to enter a random generator seed at the start so each game would have the same events happen. You would just need to monitor the game to make sure there are no unallowed addons and that people can save/restart the game.
You charge a small tournament fee, take a house fee and profit!