That may be the case, but by the way they have stated that when you start, you are assigned to a tribe, it just sounds more forced. Plus, I'm not necessarily interested in joining a tribe. I would rather just be able to survive out on my own, fighting bears and building my little shanty, Hatchet
Also, just to clear something up for ya. Prelude is the name of the first chapter of the game, not just the early release. It's like a subtitle. When the game officially launches, it will still be called prelude until the first free expansion. At least, that's the way I understand it.