So, we have two options: aliens or developed
> extremely ancient human culture, which flourished
> perhaps before Stone Age.
Yes, this is the basic model that's been proposed many times over the years here. Several of us do not accept that the development of mankind has been on a single, linear, run from the cave to Mars. Rather, the physical evidence points far more clearly to many cycles of civilization, each with its own technology, and between which cam catastrophe, devastation, technological amnesia, and rebuilding...and/or extraterrestrial influence. And it all started much farther back in time than orthodoxy would have us believe.
Both things potentially could be true - that civilization is cyclical and that we see non-human involvement.