No.
This reductionism has no explanatory power. You might as well say "all egoism boils down to the benefit of the other because personal benefit benefits humanity/the universe at large. Therefore all reduces to altruism." You can pick any explanation and say "in the heart this boils down to X". If you have no special reason for choosing X (which is evident if you can explain just as much with Not-X), all such explanations are equally worthless.
There are many options other than believing that a human life divided by infinite space approaches zero.
I have no idea what you mean by a "more aesthetically pleasurable life," except that apparently it's a bad thing, but if we all truly accepted our insignificance (in the face of the cosmos, God, love, whatever) and that we often do "altruistic" things out of self-interest rather than love and compassion, the world would be an amazing place.