Has there ever been a Sci-Fi short story where the premise is:

Cafe Society
1

The reason humanity hasn’t found any intelligent life other than its own is that long, long ago…every other intelligent species in the galaxy left, but man. Stubborn man.

Basically it starts off as an end of the galaxy (or universe) story. For whatever reason every species is “moving on”. You think it’s a story about how one faces the end with dignity, but the real story is why Man is alone in the galaxy (or universe). Man refuses to give up and ultimately is left alone.

2

Yes, sort of. In one of the tales in Michael Moorcock’s Dancers At the End of Time or the other one in that series, the protagonists get an alien visitor fleeing the coming End and they ignore her.

3

Which was quite mean of them considering that their use of energy was accelerating the heat death of the universe in the first place.