When you look at some of the flint artifacts from that time period you quickly understand the skill and intelligence required. There were no books or any means of recording history so everything had to be shared verbally and remembered. Native Americans told stories of their past to the younger ones in great detail. The mental maps they had to store for life in order to navigate throughout the area. Water here, food sources there, where to find the best chert for making stone points and blades, where caches of blades and point material were hidden for further use. Running out of knappable stone was no different than running out of ammunition.
During my long life and world travels, I managed to accumulate a large collection of spear points/arrowheads I picked up along the way, and what puzzles me till today is that some of the spear points/arrowheads I picked up in Peru and Bolivia are indistinguishable from some I picked up in Afghanistan and Pakistan: identical shape, size, and knapping technique.