In one of the many debates on this topic I've participated in, one of my favorite (because it is optimistic) scenario is that we are not alone and the other civilizations are waiting to see if we kill ourselves or not before they stop by to chat.

That line of reasoning started with, "If we knew then, what we know now, would we have claimed the new world for conquest?" There are examples that we would not, for example protecting Brazilian indigenous peoples who have not contacted the outside world from being visited by people. Would "modern" western Europeans wait for the native Americans to sail east and meet them? One could hope they would. With a careful understanding of infectious diseases and respecting their traditions and culture.

It is arguably the case that we have lost much in terms of culture, ideas, and diversity through genocidal colonialism. Would a more enlightened civilization decide not to go there? I would like to think so.