According to a reliable insider, Rockstar Games intends to introduce single-player DLC for Grand Theft Auto 6, something that was very-much noticeably absent from Grand Theft Auto 5.
Seeing the success and popularity of the DLC that it release for Grand Theft Auto 4, fans expected Rockstar Games to introduce single-player post-launch content for GTA 5. However, Rockstar apparently didn't anticipate the incredible success of GTA Online, which resulted in them shifting their focus from single-player DLC to GTA Online, exclusively.
Tez2, who has been a reliable Rockstar Games insider for years now, replied to a comment on GTA Forums stating that Rockstar Games is planning on handling GTA 6 post-launch content the way they initially planned for GTA 5.
In no way does this mean that GTA Online will not receive proper support in the future. However, in addition to GTA Online, single-player fans should also be able to enjoy a multitude of post-launch content.

