Imagine this:
Rigs of Rods vehicle and vehicle damage physics(or R* engine RAGE) on vehicles, Ship Simulator Extremes seas, Flight Simulator X airplanes, GPS data roads with accurate terrain forms, and lastly, Multiplayer.
I wonder how big the game would be, I mean Max Payne 3 is already 35 GB and it's a limited area game..
Well as they say, todays dreams might be tomorrows reality.
EDIT: Some readers are starting to take this seriously, it's just imagination guys.