Their houses are wagons- wagons break down, and need parts to repair them with. No matter how good they are at fixing pots, sometimes you need a blacksmith. And even if they get around that...

They need food- (is The Way of the Leaf vegetarian? I assume so, but I can't actually remember specifically). Since they can't grow it, all they can do is gather and trade for it. Gathering is pretty tough when you're a large, constantly moving group.


So, they depend on their skills to make enough money for food, and clothes, and garish paint, and all the rest. Hardly self-sufficient.