I just read a neat article explaining that in the past, roadways were considered to be shared space beween all users - including pedestrians, cart-drivers, vendors, and streetcars. Then, Henry Ford's Model T came along, causing a huge culture clash between cars and all the other users.
And now look at us! The streets are the exclusive domain of motorized vehicles and streetcars. The amount of time pedestrians spend on them is (in theory!) tightly controlled by signal lights and crosswalks.- Bikes... well, even if you're in a Toronto bike lane, you still have to be eagle-eyed to make sure you don't get "doored", and I've had people honk and yell at me for doing things on my bicycle that are perfectly legal .
Given the amount of car traffic that exists, and the relative size and weight ratio of vehicle:bike or vehicle:pedestrain, it's not surprising that cars have taken over. And really - it's not practical or safe in modern times for people to be wandering randomly around in the same space as cars and trucks. THat would just be a bad scene all around.
Still - I'd love to see more bike lanes and shared-use space. I think that if it's properly incorporated into urban design, people will use it. And will feel encourages to make a switch out of their cars - which is what we really need in order to improve air quality.