Of those mutations, what became of the ones that lost out? Why versions of humanity were left by the wayside, along the path of evolution?

Are we ancestors of a common and small band of winning apes, who won our over those of a quite different mindset? Some tribe of fifty or so individuals that eradicated all of the competition?

In another timeline we might have evolved into speechless and peaceful gentle folk instead of the tribes of ruthless competitors that make up today’s world. And markedly less populous too, maybe, and probably without making footprints on the moon or conceiving plutonium warheads. Maybe just as likely to have done so, maybe even sooner than our current version of the species.

Yet another reason to pick up Niven’s Ringworld some time soon. In that case it was de-evolution, but the ideas feel similar.