GTA 6 using UGC could mean the return of story DLC
Rockstar could bring a story DLC due to community support.

Almost 17 years ago, Rockstar Games released Grand Theft Auto 4: The Lost and Damned, effectively hinting at a direction of prolonged support for the offline components of their future games. This direction would roughly last a whopping one and a half games — Red Dead Redemption, with the release of Undead Nightmare, and two canceled story expansions for GTA 5.