I tried your test game. Sumerians beat me to Pyramids by a couple of turns in 2000 BC. My score was 288 +4 ppt. This suffers from not having a 3rd food bonus, forests, and having to move T1 but in comparison to your score of 281 at 1790 BC is 10% higher with an exponential growth rate. I will replay but I do not know what you are trying to argue. 3 cities is better for score and you build Pyr at approximately the same time (+-2 turns). Tried again, again Sumeria built the Pyramids.