The development schedule for GTA VI was delayed by several years. Rob Nelson, head of Rockstar North's associated studio, stated that the expanding scale of Red Dead Redemption 2 required involvement from more Rockstar studios, which was the reason for the schedule adjustment.
Nelson recalled that Rockstar employees traveled to Miami in 2015 for the initial research phase of GTA VI. The project was codenamed "Project Americas" at the time and envisioned featuring parts of North and South America on its map. This was an early concept and should not be taken as confirmation that these regions will appear in the final version.
As originally planned, Rockstar North was responsible for advancing GTA VI, while Rockstar San Diego simultaneously developed Red Dead Redemption 2. As the latter's scope expanded, Nelson believed more studios needed to be involved. To complete this Western-themed title, the development schedule for GTA VI was pushed back by several years.
Rockstar typically has multiple studios working on different projects simultaneously; currently, however, most employees across its 11 studios are concentrated on a single project.