from the perspective of sustainability the uncontacted tribe is more civilized than the ancient Romans or chinese
I heard in highschool that scale is the big issue with civilization. Anarchy, for example, can work up until people start not knowing themselves (I heard 200 then; I'd argue that this corresponds or is near of Dunbar's number 150 [1]. I don't think this was known by my teacher then, as this was first proposed in 1990 according to wikipedia).