Why so much variance in human intelligence?
Every dominant culture has essentially vanished in time, whereas the few cultures that still exist outside industry and technology have persisted much as they did since long before the fall of Rome. Many would say that survival and replication is the greatest accomplishment of all. Rockets are impressive but the resources necessary for their production are being consumed much faster than they can be replenished. The gene pool necessary to support those who understand calculus - to produce them and feed them, and clothe them, and carry away their waste will, in all likelihood, lead to the demise of the culture. There will be isolated tribes of hunter gatherers until the sun engulfs them all.