Just look at the difference between https://www.populationpyramid.net/united-states-of-america/1978/ https://www.populationpyramid.net/united-states-of-america/

Just look at the difference between https://www.populationpyramid.net/united-states-of-america/1978/ https://www.populationpyramid.net/united-states-of-america/1... and https://www.populationpyramid.net/united-states-of-america/2018/ https://www.populationpyramid.net/united-states-of-america/2... . Also look at world population change in the same period. I don't see that discussed much but when the shape of populations change (which causes how things are funded to change as well and where resources are used) society has to change too but that is a lot harder and takes a lot longer.