In regards to the claims that he works 11 hours on the game per day.
I don't believe it either, but I'll point out that working on the game doesn't necessarily mean progress is being made. I figure that he is the type that'd create several images, only to delete them and start over again. So, while he may only produce 5 renders per day that'll actually be in the game, he really makes double if not triple that. He just deletes them when they're not perfectly what he wanted. That is the only thing that makes sense, according to some posters here his PC can render in minutes. He should be able get 5 renders out in 1 hour, let alone 11 hours.
This game is just very inefficient from a development perspective at pretty much every turn.