No kidding. Check out this blog to see what difference street width makes. The author narrowed LA's streets using Photoshop and it instantly feels more livable: http://narrowstreetsla.blogspot.de
It's still cars; it's just that the problem was never the automotive engine. Old World cities were patterned after layouts that were based around people walking. Then we started riding horses, pulling around carriages, etc. By the time you get to the Western frontier, the vast open space inclines you to spread out your buildings.
http://www.newworldeconomics.com/archives/2013/112413.html