I wonder if by the time we solve a 'theory of everything' (or understand by some other means the basic mechanisms of our universe), we'll be able to efficiently, procedurally, generate a simulated universe.

Also, the Fermi paradox could be a solution - we don't see any other alien life forms because we're running in a computationally limited simulator, and everything outside our (relatively easy to simulate) solar system is running on minimum resolution (so to speak).