This doesn't match my experience. I see bikers mainly in the city bikeways, just not in the most crowded and well-transit-served downtown core. In suburds the miles add up too quickly and take up too much time. It may depend on how dense your cities are.
Biking looks time consuming, but if you use it as time for exercise and sunshine-time you would otherwise be doing on your free time, it's almost 0 marginal cost.