Your intuition is probably wrong: off-the-shelf consumer-grade microphones can typically gather 44.1-96k samples per second at 16-24 bits per sample. That's a lot of potential information.

Also, consider that your ear/brain apparatus estimates object positions and occlusions from audio signals all the time.

Also also, the eighteen-wheeler problem is vastly different from the finger problem, as the latter is smaller, slower, and closer to the microphone, each by 1-2 orders of magnitude.