>While the quality of life really is objectively better with children, the secret to these rankings is probably the calibration inherent in the question.

that's not really a secret or calibration issue though, that gets to the core of what happiness is, a relational property between expectation and reality. It's not an objective measure like income or height.

I don't think the notion of an 'objective' quality of life even makes a lot of sense. Quality of life is always measured against some concrete alternative, not against some abstract scale or points based system. Two people are going to have very different attitudes towards some way of life purely depending on what direction they come from.