To the point of them revisiting the same cities time and time again, instead of any new setting. To be fair the tech at the time only allowed them to do so much with the original Vice City.
Now they are not really held back by old tech, so they can really do vice city justice.
Also, The original cities remain some of the most popular games of all time. So there is massive demand from the fanbase to revisit the old settings, as people want to see vice city again but on a grander scale and with new graphics.
So I don't mind returning to VC. That said I think for 7 which is god knows how long away, we defo need a new setting.