Bench press is an American enigma. The clean and overhead press used to be in the Olys. Overhead press was the standard for upper body strength until that event was removed from the Olys, and powerlifting took off in USA at the same time (early 70's) The powerlifters adopted bench press for several reasons. Most of the big lifters in the world do cleans and snatches. Powerlifters do the 3 we recognize.
The chest muscles, I believe, are more of a North American-based look at the physical manifestation of power. Much of the rest of the world seems to be more into legs - developed with low squats, and shown in the form of rugby shorts and speedos!
As for fighters - well, funny you picked 3 non-Americans, but, overall, this is something I noticed years ago, too. Wanderlei was super-jacked in his day, and was tight but not huge in the chest, as opposed to what I was used to with every big dude on tv. Bas Rutten, same deal.... chest muscles are not very important to fighting, or much other than becnhing, really. It isn't a functional move, unlike deadlift - which translates to everything. Reminds me - Gustafsson just mentioned his lifting numbers - 540lb deadlift, which is really solid for a tall guy who isn't primarily a lifter. And a 245lb bench - which is basically fuck all.
