I was wondering the same thing. The office building I work in has the first four floors devoted to a parking garage, with floors 5 to 10 as office space. Why couldn't the same be done for housing?
Correlation != causation.
You can also directly compare regions in which monoliths break the flow small/frequent storefronts. The relationship, in my casual observation, holds very strongly.
You can disrupt the pattern by providing street-level temporary equivalents, e.g., street fairs / farmer's markets, and the like.
And obxkcd: http://xkcd.com/552/
"Correlation doesn't imply causation, but it does waggle its eyebrows suggestively and gesture furtively while mouthing 'look over there'."
You can see the garage entrance to the left, and the garage wraps around behind the main entrance (a five story open air atrium) to the right hand side. It doesn't have to be hideous.
Nobody cares what this building looks like because nobody would walk to or past it because it's in the middle of nowhere and there are literally no sidewalks.
This article is about a real city where people walk to things. Here is a picture of it. https://www.google.com/maps/preview#!q=ballard+seattle&data=...