I wonder, if you exterminated every gypsy in the world, whether a new form of gypsy would spontaneously generate. It seems like too inviting an ecological niche to go unoccupied, feeding off the crumbs of advanced societies. All it would require is a new group with similar high ethnic chauvinism and extremely antisocial attitudes to other groups.

In a way blacks are our gypsies, a largely unevolved, backwards parasite on productive society with high self-regard and antipathy for cooperative behavior. They aren't quite as nasty and cockroach-like yet they make up for it by being extra violent.