Unfortunately biking isn't an option for everyone. I think I once heard the average commute for an American citizen was 30 miles (60 miles round trip). That's a lot of biking every day, and not every workplace has a shower or something to freshen up after such a long trek.
I just went and looked at various sources and it looks like 16 miles was the national average for a one-way commute. Which is honestly too much for most people. On the other hand, if the average is 16, that means there are a large number of people who are closer. If I recall correctly approximately 25% of people are within 5 miles of their work. Five miles is doable by just about anyone. Not to mention many people can do multimodal commutes (i.e. drive to a park and ride and then bike from there, or bus/bike, or train/bike). There are lots of alternatives if you think about the issue some.
I know a lot of people that live way too far to bike the commute, mostly because they have kids and either want to live somewhere with a good school system or because they work in a shady area.
Plus you have to consider that some settings aren't very bike-friendly.
In my experience people blow these issues up because what they really want is an excuse not to bike. People resist change, it's *so* easy to get in the car and turn the key. It's hard to change your habits and lifestyle and start using the bike more.
Making biking easier doesn't work, making driving harder does. As gas prices go up and traffic gets worse, I see more cyclists on the road.
1 + 1 = 3, for large values of 1.