Why do people not perceive sounds lower or higher from 16 Hz to 20 thousand Hz

Human ears have sensors that convert audible vibrations through a series of physical connections to a fluid-filled chamber. These two chambers contain small levers (hairs) that are mechanically connected to the nerves that detect their movements. The hairs vary in length, each of which can exhibit a narrow range of vibrations near its resonant frequency.
For humans, the longest hairs resonate in the tens of hertz range, which is the shortest range of 15-20 Hz. It is these sensors that limit the frequency range.