I Mean look. Vice City started right after III. San Andreas a couple of months later. While another group worked on the 'Stories' trilogy. Rockstar started GTA 4 right after GTA SA's releases. GTA TLAD & TBOGT started production even before GTA 4 came out, & GTA V started production as soon as GTA 4 went gold. So i guess, They are SAYING that they are busy with GTA Online but i think early stages of GTA VI Development has already started. Thats what they always do.