So imagine this scenario:
Sapience (which I define as Human-like intelligence or better) is a relatively common occurence once a life-form is on a specific brain-arms-race path like Hominids have been for a few million years. A certain set of mutations can occur that make a dramatic difference in overall capability, so the jumps in capacity are large.
Now various types of hominids (say some version of Neanderthals) suddenly develop a technological civilization. The smarter they are compared to us, the faster the relative rise of their civilization. Instead of 15,000 years from agriculture to space age, it only takes them 1,500 years. After a brief early space age, they either wipe themselves out with MAD-type weapons, or more likely decide to leave the "Cradle" as an ecological preserve of sorts as they expand out in space (or transcend space altogether). Tens of thousands of years later, a different branch of hominids attains sapience, and the cycle repeats.
My question is 3-fold:
Name the one most important factor that would make this scenario implausible (say, hominids before this or that era were physically unable to speak), or if you prefer, more plausible (for instance the larger brains of Neanderthals).
Do you think (m)any XXI-th century level artefacts could be preserved well enough to be detectable from 30-50k ago (especially given the dramatic changes in sea-shore levels in the past 50k)
What would the one most important result of this type of 'pulsar' intelligence be in terms of pulse-driven changes across different intelligence bursts? I'm thinking for instance that the next post-human pulse for instance would have a lot less coal and oil. Perhaps they trigger (the end?) of an ice-age, or genetically modify their successor race before they leave.
Feel free to answer 1,2,3 or any combination thereof.
