Their data supposedly comes from "Sverdrup, H. U., Koca, D. & Schlyter, P. BioPhys. Econ. Res. Qual.2, 8 (2017)" Vague reference, no title. This seems to be "BioPhysical Economics and Resource Quality", which is a Springer publication. Here's the actual article, "A Simple System Dynamics Model for the Global Production Rate of Sand, Gravel, Crushed Rock and Stone, Market Prices and Long-Term Supply Embedded into the…
So your objection is somewhat like claiming oxygen starvation by fire is impossible since the atmosphere as a whole is 20% oxygen. It's what's near you that matters, and the local impacts of sand and gravel mining are often severe. As the Nature article notes:
Desert sand grains are too smooth to be useful, and most of the angular sand that is suitable for industry comes from rivers (less than 1% of the world’s land).
Riparian ecosystems are generally the most productive of terrestrial (vs. marine) zones, and activities at one point on a river will have major impacts downstream and even offshore.[2]
Another excellent reference on physical resource use is Vaclav Smil's Making the Modern World https://www.worldcat.org/title/making-the-modern-world/oclc/...
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Notes:
1. Which suggests strongly that frictions may be the most effective antimonopoly measures, and low-friction sectors tend strongly toward monopoly.
2. E.g., the Mississippi River dead zone in the Gulf of Mexico, much of which is a consequence of Chicago toilets, 2000km north. As well as ag activity along the Mississippi-Missouri-Ohio-Arkansas-Red river system.