Why can't you configure/map controls on most PS3 games?

I'm used to PC games that allow you to fully configure the controls/buttons of most games, and I've been annoyed by the lack of this option of most PS3 games that I own. At most, you get a few different configurations to choose from, but rarely do you get to configure every control/button (besides analog stick controls that need to be on the analog stick). It would especially be nice in sports games so that you could use the same control setup for different sports games (e.g. NBA Live, NBA 2K8, etc.), or for games like COD4 where you just hate a certain control like pressing L3 to run. Yeah, there's no point of this thread but it's weird why developers don't give the consumer some flexibility in setting up the controls to a game, which ought to be a simple thing to do.