It was a poll for the communty taken by the devs. in 1.0.

The community wanted zones that where richer and livelier, livlier, live-lyer? something. And after that option it was stated that if we select this option than there would be zones. and the community still picked it. It is still very possible to go zone less but with the type of environment in the zones you would need one hell of a machine to do it which i think was one of the downfalls of 1.0 only like what 5% of the population that wanted to play it had a computer capable of playing it.