This is something that gets hammered on in Archeology and Anthropology - People have always been extremely skilled and inventive within the limits of the tools they have available. There's no such thing as "primitive" people or primitive tools. People making stone tools selected the best materials and often transported obsidian and other desirable materials hundreds of miles. Impressive mining operations were conducted to exploit veins of flint and chert. Skilled workers could produce many different kinds of tools and blades. A skilled flint-knapper can visualize and then produce a desired shape rapidly using a very nuanced understanding of how the stone flakes and chips. A single cobble could be shaped to produce numerous different tools, or the worker could focus on making one specific, highly refined tool. And the result was the sharpest blades that it is physically possible to make without bonkers 21st century material sciences.

In all these survival video games you see stone tools that are just a rock tied to a stick, but irl stone tools were made with great care and precision.