Egalitarianism is not a conclusion reached after some thinking about it.
It is an arbitrary starting premise. And people who defend this premise always presuppose it to be valid in order to be prove it to be valid. It’s depressingly circular.
Egalitarianism is a substitute religion, because the end result of egalitarianism is only egalitarianism. Any question about an important meaningful life is irrelevant here.