Well technically JKD is not a system as much as a philosophy. Bruce was comfortable in his skill set and what worked for him, and he always encouraged others to do the same. Whether it be Kung Fu, Muay Thai or Karate..JKD encourages one to find the most effective technique for the given situation. If your push kick is more effective (due to your reach), then say a lunging punch...then use it. Bruce was bothered by the fact that JKD may become stylized and systematic and hence always referred to it as a philosophy.
Let me get this straight. You are trapped in a cage...with an opponent of equal size....for 15 minutes..... and yet you still couldn't defeat him?. What use is your art?