There are tramps in every society. Even in rich countries which have comprehensive Welfare arrangements. A popular idea of a tramp in England is the ragged alcoholic who stops you in the street to beg 10p 'for a cup of tea'. But the majority of homeless people are very different from this stereotype.
People find themselves 'on the streets' for all kinds of reasons.
Sometimes it is the result of dire economic circumstances. Usually it is a combination of factors. Life is hard and hostile for the jobless and homeless. But some people actually choose to drop out of society. The open road has a romantic appeal.