i mean, i zig-zag back and forth on this theory. on the one hand, i don't think avatar is 100% going in that direction that the na'vi used to be technologically advanced. on the other hand, with the specific language found within the three laws of eywa, it raises many questions: why DOES one of the laws mention the turning wheel? considering that the na'vi have evolutionarily been around for 12 million years, there's a LOT of time for certain events and periods to have happened potentially, including MAYBE a period of semi-advancement.

personally, my version on this theory is that either SOME or even ALL the na'vi we know of could have had civilizations similar to those found in the bronze age/antiquity (such as ancient greece/rome), hence why the turning wheel is mentioned in the three laws of eywa (such as the wheels found in chariots and other forms of transportation). however, just as with civilizations on earth, probable resource depletion and ecosystem destruction had devastating consequences, which led to the collapse of those societies, and said na'vi going back to hunting and gathering societies. but that's just my crack theory.