Quite a few people choose simpler lives voluntarily. If they're happy, that's fantastic, they made the right choice. I de-clutter occasionally, which is a similar choice. But I see no reason that any style of life could be without deep-rooted problems. Ours is most likely ennui; I'll take that, because it's a personal problem that can be battled personally, and solved. Our culture could be better for such things, but not without other costs / problems which really can't be predicted, so I won't try. Many more "primitive" cultures have problems which are less solvable by individuals - food, safety, health, and yes I'm oversimplifying and it could be insulting, but it's more true of smaller, more isolated, less-technologically-advanced cultures than it is of the rest of the world.
We have far more individual options than they do, if only because we can choose to do without them (see: Amish). Which may be the root of the problems with our culture. But I like personal problems. I can fix them. I can't fix society as easily.
edit: I've enjoyed it too :)
Good intentions almost always fail. People deserve respect. Superiority is often an illusion. Motivations are multifaceted.
I know I'd be happier with a simple life, and - perhaps romantically - I imagine that these people might have a better life than we do. Realistically, that's just as likely as the opposite - because, for all the interesting things our lives have to offer, there are some deep-routed problems we face, that we're very far from solving.
I think I said it in another post - but I'll reiterate before signing off .. I really hope this tribe is left alone. If a lot of contact is made, I'm sure no good will come from it.
EDIT: Nice debating with you btw.