Why are footsteps so loud?

I know the sound effects guys have to make a buck, but...

I guarantee you, if I'm sneaking around a place looking for someone, you can bet I WON'T be wearing shoes with leather heels, or otherwise make so much noise.

In the scene near the end when the John Voight character is prowling through that warehouse looking for Mandy Lee (or whoever), his footsteps being so loud would have let ANYONE know he was there, and where he was.

Surely, the director must realize that the viewers can see him walking, so we don't need the audible clue of LOUD footsteps to let us know he's walking.

And, that's not just is this movie, either. I notice it in almost every film I watch where there is a sneaking, search scenario.