Ya know, I like the metric system as much as the next guy, but let's be fair here. One is based on a foot, something most people have on their person at any given time. The other is based on 1,000,000th of the distance between the Earth's equator and pole. How many of us walk around with one of those in our pockets, eh?
Also, has anybody older than twelve ever had to know how many feet were in a mile with an accuracy greater than "I dunno, five thousand and some shit?"