You rarely hear drug commercials on the radio. Television's a different story... every other commercial is for a drug to fix your stomach problems, sleep disturbances or allergy issues - all ending with a laundry list of side effects, disguised by distracting images of happy people playing over the monologue. You can't pull off that off with radio.
No one would entertain the thought of walking around with just one shoe on. Not only would it look funny, but it would be really bad for your feet, knees, hips, back and even your neck. Unfortunately, many people have been doing this very thing for years without knowing it!