More ambitious projects need a certain critical mass of resources behind them. Ancient Egyptian civilization built a large irrigation system to make the best use of the Nile floodwaters for agriculture, a feat that would not have been possible to a small tribe or chiefdom.
This doesn't mean people, we're no longer bound by labour intensive solutions.I live in a single state with a tiny population that mines and ships 16x more raw iron ore, almost a billion tonnes per annum, than peak annual iron ore mining in the entire USofA ever. We also mine a millions of tonnes of other resources. This is entirely down to bigger machines, smarter technology, and factors that don't require more people.
The arguments presented here for even more people on the globe are sketchy at best, no weight at all is given to the downsides of truly challenging levels of resource extraction currently at play to meet the high consumption demands of a small proportion of the large population we already have on the planet.