User generated content is what these games (mods) lived off of back in the day. With out user generated content I might as well get a 4k tv and a next gen console. 
That is what a game community is/was. People getting together and HELPING the devs improve the game / gameplay. We didn’t have to rely on 4 or 5 devs to churn out a new map every month, we had hundreds of level designers each churning out 1 every 6 months in their free time. Some were great, some were giant boxes, I loved the killbox maps in HL:DM, or the 1v1 arena maps in TFC. There was an entire ecosystem of addon development that has recently vanished thanks to locked down or unreleased SDK’s and DLC.
I’ve boughten entire games just to play the mods they offered, surprise: I’ve never played the original HL single player lol, But I probably had well over 4k hours in HL Multiplayer, and I don’t even want to think about CS… A games life is extended through the community because its an exceptional base that inspires people to help it.
Remember when developers would release new maps and features as patches, not DLC?
The model has changed, it is now about getting the most money from your current user base instead growing it. It was about getting money from new users BECAUSE of your user base. It’s literally free money after the game is stable.
Look at valve, how many mods have they turned into full games? All because their users helped the community. They literally wrote one game and sat back and cashed in because of all the mods. People were still buying HL when it was 5 years old because it was still a “new game” thanks to the community. How many people are buying BF3 today? How much money did they have to pump into BF4 only 2 years later?
/rant