If it was remotely normal for a plane to take that much damage and live, lotsa folks would get frustrated (well, more than they are NOW) and quit the game.
Man I've read that book at least 5 times since I was 10 years old in 1970--went to the 8th Air Force museum in Savannah, and Johnson was given very little attention compared to several of the others in the 56th. I always had the impression he wasn't well-thought of