Two-toned up/down multi families

[Charles Wiegert]

Dumb question, but its always bothered me. Why are some two, three, four family houses two toned? Either different color siding on the first level than the rest or a different siding all together. Was there a huge bubble at one point where all these additions were raised? I just think that the buildings in general would look a 100 times better if they were all the same. I post in Connecticut because im not sure if its a national trend or just my part of the world.