Naked all the time is impractical, for all the reasons mentioned above. What could certainly happen, though, is a society where most people undress at home, when entertaining friends, and so on. Hans Peter Duerr has written a fair bit about how most societies where nudity is commonplace have quite ingrained rules about how and where you direct your gaze; even if people walk around naked, it is still considered a sign that you're both rude and a bit dumb if you stare directly at someone's genitalia.