I think this is a key point that is often forgotten in science fiction (unless you read hard-SF). Humans/the Homo genus evolved to the point where they could communicate and use tools to the sophistication we see today over the last few hundred-thousand to million years (depending on whether or not you consider the capabilities of other species of human). However we only started to organise into non-nomadic communities in the last ten-thousand years. There is little reason why a species with these attributes couldn't have evolved at any point since the Cambrian explosion but that is just how things have gone. It would seem an extraordinary coincidence if we were to identify an alien species whose history was the same length as us and who were at roughly an equal level of technology. More likely the separation would be measured in megayears.