Sure everyone can live like "snowbirds" using only a bicycle for their transportation; just as long as they have no children in school, and no physical infirmities themselves, nor care for anyone with same, and just as long as they can live for months at a time with just what they can carry on a bicycle. I don't believe your idea of "everyone" includes many people outside of physically healthy people without dependents, and with no ambition to be in a career field better than a migrant farm worker, fast food burger flipper, or hotel maid.