Echolocation is a physical ability that we possess and has been proven by many blind people. Its primary function is currently with the blind population, and while the blind are said to have more acute hearing, it has been tested (even amongst the best echolocators) to be no "better" than the average person. They have simply been given the opportunity to put more focus on it and thus have become more in tune with its subtleties.
Hundreds of thousands of years of human development are to be attributed to the fact that we use tools, brains, and all of the physical abilities at our disposal. Echolocation is an ability that has gone unacknowledged for many thousands of these years. Certainly there have been people to use it, most likely blind, (the case of James Holman stands out as notable amongst many blind people who claimed to be able to see objects via "pressure" on their face, or "facial pressure") but it has not been brought to the attention of the mainstream public until very recently.
Imagine that the human race had never realized that it was possible to hurtle one's body through the air, curl it up into a ball, flip around and land on one's feet. The first time someone successfully landed a front tuck was a revolutionary turning point in one small area of human development. Gymnastics is an incredible ability that is not necessarily feasible for everyone, but the human race has worked hard to develop it into a sport and a form of entertainment. People teach it and practice it because it is challenging and enjoyable.
This is much like echolocation. If your parents had told you that you could hear the sound reflected off of objects, and told you "Listen to where the tree is" just like they told you "Look at what color the ball is" then you probably would have grown up with at least an acknowledgment of the existence of this ability. It is human nature for people to explore their own abilities and therefore you probably would have practiced or at least noticed this sense in your development. Now, what if people had been developing this ability for the past 10,000 years, just like the abilities of speech, walking or running. Imagine where we would be. The world of darkness and blindness would be so much less foreign to us and there would be many opportunities and abilities which inherently implement echolocation that would easily become apparent should we refine this ability.
As Eric Schwitzgebel stated in his blog Echolocation and Knowledge:
...most of us, even if not wrong in quite that way, are strikingly ignorant about this aspect of our stream of experience.
We have so much room for development in the area of echolocation, and so much to learn. I'm glad that we have not reached the final plateau in learning about ourselves (although I know that would be an outright impossibility).