Yeah; what I wrote was absurd. Most civilisations can trivially be improved; we're definitely pretty high up the possibilities. I meant we're not in the top 20% of feasible possible civilisations anybody currently alive would want to put into place (which is a qualitative claim, not a quantitative one).
This sort of an unmeasurable goal. I think we’re certainly in the top 20% of civilization from any time in history. Or top 20% ever attempted.
It’s hard to tell how good all possible civilizations can be.