So you implicitly suggest that all people share the same principles of life and moral values. It may be true for a small isolated group of people and your idea of ostracism and outlawry may actually work between them. But if you take some larger proportion of population and apply this principle among them you will see tensions arise and eventually you will end up with fractions denying and neglecting each other (if not fighting)... 
Probably. But if they have their own spaces, like minded people will gather. They may even decide to form coercive governments. But if decentralization is common, and people have learned to be independent, those will be pockets.
But what about economics? To sustain the achieved standard of life we need that tight hierarchical integration between people (ironically called division of labor) which most anarchists loathe as much as they are afraid of...