Why are classic 4 door sedans "disliked"?

There was a thing even as a kid in the 70s where a 4 door just wasnt desireable. I remember being in high school, in the 80s and a guy had a 69 Chevelle wagon. I told him "its a neat car shame its a wagon..." just the way it was...or is LOL!
Friend of mine traded a very nice Cougar XR7 for a more door Chevelle with big tires and aluminum slot wheels. Told him he got ripped off in the deal. He totalled the Chevelle about 2 months later.