I agree that bicycle commuting isn't realistic for a lot of people (although it is realistic for plenty of people who don't do it currently) because they live so far from where they work; and in lots of places, even using a bike for short trips is dangerous and not feasible, or even basic shopping is also fairly far away.

But any discussion of long term goals for efficient transportation needs to include long term development planning. An important goal in my mind should be bringing residences, workplaces, and shopping closer together so that more transportation options are viable. In far-flung suburbs where most people work at least 20 miles away and most shopping is 5-10 miles away, driving will always be the most convenient option. (Not that plenty of people aren't capable of riding 5-10 mi to the grocery store, but if you are just making dinner and realize you're out of bread or something, are you going to take two hours to go get it?)

Building denser, more walkable communities closer to where jobs are is how you get a variety of transit options to be viable. Most people around where I live could conceivably bike to work, or take public transit (and they usually have several choices of routes), or carpool with a coworker who doesn't live too far away, and in many cases even walk. Whichever way they get there, it's a choice. For people who spend an hour in the car on the highway between the subdivision and the office park, it isn't much of one.