Gatorboy is right, it does smell fishy...
For what it's worth, archaeologists are currently looking at Marvin McCormicks workshops. He was a flint knapper who turned out hundreds of thousands of Alibates points over the course of many decades. I saw a picture on another site of the area where Rinehart made his grey ghosts, his waste piles cover acres with, waste flakes, slabs, broken bifaces, rejects, etc.
A prolific knapper can go through tonnes of material (literally thousands and thousands of pounds of material) a year if they are churning out pieces. A lot of this could have been a knappers pile (with some extra pieces from the knapper tossed in.)
On the ancient end most quarry sites used to look like that before collectors started picking things up. And they aren't really caches in the sense of the word that most collectors use. Alibates National Monument has more broken pieces laying around than you can imagine, it's almost painful for collectors to go and see it. I have seen pictures of some of the high elevation obsidian quarries in California, and the number of rejected obsidian bifaces is amazing. They hammered them out, and carried down the best ones. At other obsidian quarries the bifaces were cores for flakes to make birdpoints, and the left over cores are laying around by the thousands.