If you look at more open empty-hand fighting, like UFC, the techniques of BJJ are low percentage. Most of them have their roots in the same period of Japanese history.
Now, let's look at the most successful empty-hand techniques: wrestling takedowns, ground and pound, boxing/muay thai, chokes, blocking punches/kicks, and using the guard to minimize the effect of strikes.
All techniques are low percentage in these type of environments (resisting opponents of similar skill and size). How many punches, kicks, takedowns, subsmissions et c. are exchanged or tried withouth success?