dont forget that the style today is larger than it used to be. The styling is such that people need to see the wheel well filled out all the way, which is very unlike the old days. In those days the biggest car tire you could buy was 15". Now economy cars come with bigger than that. Call it a fad if you want but I dont think tires and wheels will be getting smaller again in my lifetime, unless we all have to start driving electric carts.
So yeah, with me anyway its just as much about the look as it is anything else.