Very true. These things do still exist for a lot of games. It lost popularity a lot on CS due to the incessant need for “competitive” matchmaking, but they are still out there. Rust is a good game for heavily modded servers (if you like the game concept in the first place) and I think Arma (which a bit more niche) is basically all community servers, ranging from in depth military reality to role playing much more mundane stuff.