"It remains to be seen if human meta-cognition turns out to be an advance or an evolutionary dead end."

I'd say that each of us casts the ballot via the way of life with each and every choice made. I'm honestly reluctant to make predictions in this regard but meta-cognition is clearly an advance. Whether it will be the human one that survives, remains for now an open question as you say.

"Symbolically, one could argue that the "human leap" from self-awareness to meta-cognition was the Biblical Fall from Grace."

Yes, it really seems to be a collective memory preserved as myth. Quite insane if you consider that that memory is on average c. 75,000 years old. On the other hand, I see the fall more as the subsequent shift toward ritual survival pragmatism.

"Hopefully our self-obsession will turn out to be a middle stage [...] human civilization as we know it is our pupae stage. [...] We just can't see it yet."

I wouldn't say that civilization per se, even with parts of it as we know it, is the detour -- we would have toys and art no matter the kind of (inevitable!) civilization because meta-cognition by definition implies creativity as well as more refined modes of communication i.e. networking.

But I agree, we are still in the process of evolution in this regard. However, I think that, more than pupae and butterfly, our current stage is akin to learning to walk -- it cannot happen by itself, it requires our voluntary participation. At least by making a willful choice.