the gracie thing is probably right but thay come from a time when no one was grappling and thay did win all there fights so i wouldnt call it arrogence.
really though who cares? how many times do you get into streetfights? the ironic thing is, if your training alot then your not going to the sort of places were your likely to get into a fight. if your worried about it that much dont go to shit holes. i know plenty of people who have never got into a fight in there lives and probably never will and the poeple who do are generally looking for it or more accuratly not looking to avoid it.
you should train for fun or fitness or competiong ect but training for something that may happen to you once or twice in your life seems a bit pointless to me. just buy a dog.