Primates evolved six million years ago here. There are plenty of stars billions of years older than our sun (and still sufficiently enriched with heavy elements from prior stellar generations) where they could have, so that their signals would have reached us by now. The past light cone is everything you see in the sky. Even a million light-years from neighboring galaxies is small compared to the time scale of possibilities on the order of multiple billions of years.
I, embarrassingly, have a crackpot theory where G isn't a constant. I'll spare HN; it would make me sound like a moron.