I never believed it was open source. I believed it was as close as you could get in a live service game with any chance of survival. The suggestions above are Fortnite and Roblox. I think we can all say s&box is a huge leap in the right direction comparatively.

You post two comments. One a complaint that the game I suggest isn’t fully FOSS, and another saying the business model wouldn’t work if it was FOSS. It’s almost like I suggested the closest you can get.

It’s the same kind of game mode browser as Roblox. It’s not that big yet but it’s from the people who made Garry’s mod so i bet it’ll stick around long enough to reach a critical mass of different games to play and developers working on new ones. I hope it takes off because it’s basically the steam version of Roblox or Fortnite.

As a dev or asset maker you can make commission on the game modes/ items/ art you upload to the workshop based on how much other people use it.

It’s called s&box