What a lot of you are failing to realize is that the most important factor in a street fight is the willingness of one person to inflict real pain to another.
Another thing to consider is that there are many variables in a street fight. While BJJ is probably the best martial art to know in a one-on-one situation, it doesn't prepare you for what to do if your opponent has a weapon, or if he has friends.
Trying to triangle choke someone on the ground isnt going to do much good if 6 of the guys friends are ready to kick your head in, for your effort.