Well, not everyone kept a horse. People often just walked. Eventually communities and neighborhoods were designed around the idea that most people had cars. Retail is often kept separate from residential so that walking is impractical. So it's not just that cars are so useful, we've built our infrastructure in such a way that they're often required where they weren't before.

There are certain relatives who live outside the city that think I'm kind of a freak for riding my bike to work. We're getting to the point that it's kind of weird not to have a cellphone. The disappearance of pay phones is one consequence. And don't forget. All these little things need to be charged which only adds to our appetite for electricity. A standard telephone handset only requires power when it's actually in use.