Very true, Jer, and yet, slightly off, and I'll explain in a second.  Look at the monk that created the Crane style.  While in the garden one day, a monk saw a crane ravaging the garden area, and so he came at it with a staff.  But with each strike, the crane drew back, and then darted forward.  By watching the movements of the crane, the monk developed a system that provided a great defense and an offense against several bandits later that year.  Even if you look at other animals, you can see their martial and civil behaviors.  The snake, always coils his body, giving his attacker the idea that he is small and incapable of attack.  But when the attacker comes forth, the snake darts forward to attack, moving up to half of his body length within one second.  So from this, it is understood that we learn from others, whether they be human or of the natural world.  So while it might be true to say we don't exactly need human instructors, because we can learn from the natural world.  However, since there is no such thing as free will, but rather, cause and effect thinking that truly exists, one can see that as human beings, we learn from everything else in the world, but seem to not have a natural fighting method, unless you count Grog hitting Ugg in the head with a stone or a large heavy club.  Well, where did animals learn from to find out how to attack?  Through animals, the ability to defend and attack is inherent; that is, it is a collective unconscious built from years and years of generation after generation of the active need for defense and attack for the purposes of survival.  As human beings, though, survival as become less and less a problem for us over the centuries.  For instance, would a young child in America today look at the way a dog moves to see how it defends and attacks?  Probably not.  The kid will most likely go to the much less effective McDojo around the corner in some mall.  And that's what the world has broken down to, due us lacking the need to an unstoppable martial/civil way.