That reads as somewhat misguided and dismissive. You don't have to understand the chemistry to improve recipes by trial and error, over multiple generations, and learn from the still-standing structures.

And there is still value in studying today those that survived in order to improve ours. The way lime healed cracks is new to me at least, but it's taken as a given here.

> you wouldn't build anything worthwhile

You just need more cement, it could be replaced with fibers. We still use unreinforced concrete in some cases.