That's true, but a brick still requires a sophisticated set of knowledge which we accept to be public domain by this point, after a few thousand years.
You need to know how to make and fire clay, what sorts of additives can help, how to package and ship them en masse...
There are a lot of problems involved in bricks. OSHA once categorized bricks as hazardous materials (don't breathe the dust when grinding them). We've just gotten really good at dealing with those problems because of how useful bricks are and how easy it is to teach people about making them.
Anecdotally, I once took an archaeology course in college, and we had a guest speaker come in who knew how to do flint-knapping[1]. Like, prehistoric toolmaking out of volcanic rocks. I'll bet you'd run into some real hurtles trying to market an obsidian knife today, if you didn't have experience in that area.
You need to know how to make and fire clay, what sorts of additives can help, how to package and ship them en masse...
There are a lot of problems involved in bricks. OSHA once categorized bricks as hazardous materials (don't breathe the dust when grinding them). We've just gotten really good at dealing with those problems because of how useful bricks are and how easy it is to teach people about making them.
Anecdotally, I once took an archaeology course in college, and we had a guest speaker come in who knew how to do flint-knapping[1]. Like, prehistoric toolmaking out of volcanic rocks. I'll bet you'd run into some real hurtles trying to market an obsidian knife today, if you didn't have experience in that area.
[1]: https://en.wikipedia.org/wiki/Knapping