... and optimization. There was a previous cycle which went: GTA3 (Liberty), GTA Vice City, and GTA San Andreas. The New York game opened the series on that particular set of platforms, and Los Angeles ended it, and it had to be that way because only through endless tweaking and optimization could a game as huge as GTA:SA be released. It was impossible for me to imagine, when I first saw GTA3, that a world twenty times its size would be possible on the same console.
I think we're seeing the same thing here. GTA IV opened Rockstar's efforts on the PS3/360, then instead of a Vice City there were two expansions using the same map. Now this one will close out efforts on the current consoles.
It's worth noting that they're pushing hard to get this game out the door before the new consoles come out. I cannot help wondering if Rockstar is thinking the same thing I'm thinking, which is that Microsoft's effort--a consumer spying operation, really--is going to completely tank and Sony, once they are the undisputed king of the hill, will return to being the assholes they've always wanted to be, and demand a hand in content creation which Rockstar won't want to give them.
This may well be the last and the greatest of the GTA epics.