Per this article:
http://www.cnn.com/2006/WORLD/meast/11/04/war.games.ap/index.html
a 1999 war games study said it would take 400K troops to control Iraq and even that many would not guarantee success. That is, even with that number of troops it might end up just as it has. I feel confident that if Bush ever knew of this study he completely ignored it because of another of his gut feelings.
As far as giving GWB more time for his policies to work, three years of "staying the course" resulting in the current state of affairs is rather indicative that his policies are not working and aren't going to. My apologies...., I forgot he hasn't really been "staying the course".
I think GWB always stays the course because to alter course would be to admit he made a mistake and GWB is apparently incapable of admittting he made a mistake.