Arguably, the advances we have now in modern day is because we have generally decided that everyone should be able to read, write, do arithmetic. Now we have a massive funnel (the entire generation) to do innovation. This is a much larger pool than was possible with a very narrow subset of the population capable of these things.

We also know that stress and poverty actually reduce the brain's capacity to think, and even moreso, a child who suffers from stress/hunger/general poverty has a stunted brain development due to exposure to stress in their formative years. So, naturally, we can say that not having systematic stressors like hunger, economic insecurity, health concerns, etc. would lead people to have greater capacity for wonderful things.