The Fallacy of the "Automobile"
While horses present an inconvenient form of transportation, the modern automobile doesn't exactly propel itself without needs. Whatever resources a horse may require, a car has a much more extensive list. Gasoline, parts, maintenance, and most importantly lots of roads. Sure its got an engine, but you won't get far without those trillions of dollars invested in our highway network. In the end, I find both horses and cars a great nuisance.
The freedom of transportation that a car offers is great, but the sad fact is that I am carrying 3,000 lb of useless metal with me everywhere I go. And then I have to find somewhere to park when I arrive. The parking issue becomes very important in large cities. This interesting post by frumination shows what NYC/Manhattan would be like if it was trying to accommodate vehicular traffic every day (via Infrastructurist). Basically mass transit is essential to a city like NYC. Just as elevators are essential to the development of tall buildings.
The US Bureau of Labor releases information how average US consumers spend their income. A recent graphic from Visual Economics summed it up quite nicely, we are spending over 1/6 of our income on car transportation each year.
A lot of people complain about the high cost of public transit system proposals, but it's obviously not more expensive than cars. If we assume that the entire population of Indianapolis, roughly 800,000 people, were to trade in their vehicles for public transit then we would free up ($8758/2.5)*800,000 = $3B per year to invest in other strategies. I bet we could find a solution with that level of funding. It won't ever happen, but it's not impossible to imagine.