A somewhat lengthy essay. Look to your laurels, Duracell.
I was introduced here to the phrase Nil admirari, the philosophy of those professing that there is nothing new under the sun. It is often the case that people cloak themselves with this in order to project an aura of world-weary wisdom which in truth they do not possess. For such people, it functions as a mask to hide intellectual cowardice.
One of the more likely resolutions IMO. Our galaxy has been humming along for at least 12 billion years in some form or other and we know that, even with modest assumptions, galactic colonisation takes only on order 0.1 billion years. It's therefore not unreasonable to posit ancient civilisations who reached equilibrium eons ago, perhaps as races of peripatetic wise gypsies.