US is worse than many developing nations when it comes to public transportation.
There is no way most people can depend on public transportation in US for regular commute. The frequency, and reach of buses/trains are incredibly poor in most of US. The exceptions are the few big cities - NYC, Chicago, Portland etc., that too if you live in an area close to a station.
Not even Bay Area - a high populated urban area - you can depend on public transportation for daily commute unless you have an option for point to point travel on BART / bus. Try going from Hayward to San Mateo - 25 minutes if you drive, more than an hour if you take a bus. You only have to cross a bridge!!!
The same with many East coast neighborhoods - try Phoenixville PA to Philadelphia on a SEPTA bus.
It sucks to be poor. But in 2015, its better to be poor in a country like India compared to US as poor as a voting block is better represented and their needs better taken care of...and that includes public transportation.
To get a better perspective on what it means to be poor in United States this book is a good beginning - http://en.wikipedia.org/wiki/Nickel_and_Dimed