> Basically, if you took 10k people and dumped 5k of them on one planet and 5k on a planet that was the physical opposite, forbid them to contact anyone, and visited 2000 years later, Generativists say you could find a system in common between the two and cognitive linguists say you probably couldn't, because the systems themselves would have evolved to have different starting points.

Is this not a bit of a false dichotomy (substantially dimensionally compressed representation of the true underlying complexity)? Like sure, one is likely to be able to find substantial commonality, but does cognitive linguistics really unequivocally assert that you will find no commonality whatsoever? If so, that seems a bit crazy.