Yes, but you have to remember that the developer community is absolutely tiny compared to the number of gamers.

It’s a neat gimmick, but 98% of the people who could be your audience will get nothing out of the game being open source.

I would really like it if certain specific games were more open source and more moddable, for example stellaris has an annoying formula hard coded that makes combat balancing and weapon modding very difficult. On the other hand, games like openRA exist and I’m not playing that and I’m not doing anything with the source either. That one even has fully functioning multiplayer, but it’s so built in that it’s hard to reuse for anything else. So you might end up being torn between making the game really good and making the tools and code really good.

I think the biggest appeal of open source games is as a learning resource. Maybe. idk.

Also, may I suggest panda3d, which I’m shilling for at every opportunity that I get, because it’s neat, 3d, open source and runs with C or python?