Maybe people participating willingly in those societies—indeed, fleeing civilization en masse to the frontier and to join "Indian" tribes, while migration from the tribes to the civilized colonies was almost nil—should tell us that civilization isn't all upside?

Economic productivity is an important means to happiness, because it sucks to go blind or subsist on soft foods because you can't get the necessary medical and dental treatments. And it's terrible to never see your parents again because you don't have the material means to visit them. But there's a point of diminishing returns beyond which sacrificing more of your happiness for continued economic gains amounts to cutting off your nose to spite your face.

You could replace the word "advanced" with "unsustainable" and the thought still holds.

No, unsustainable societies like the Lykov family or the Tasmanians were also often unspecialized. I suspect that specialization improves sustainability in general, at least up to a point. But it depends on how it's structured. The Khwarezmian empire had a high degree of specialization for the time, but one bad decision by the emperor made it unsustainable.