The one thing that gets me about this is that the city blocks in GTA IV seem smaller than the GTA V blocks. To me, that says the GTA V map is a bit smaller than we think, but only maybe by like 10%.
Anyway, I think I heard the map has about 21 square miles of land. Pretty big, but after playing ARMA III that sounds like nothing.
Honestly, I think the opposite is going to happen. People could be so satisfied with GTA V that they won't see any reason to upgrade to the new consoles immediately.
There's all these issues with second drivers (Massa and Webber especially) either not pulling their weight or always having a fit... it really makes me appreciate Barrichello for being such a good backup.