> Concrete alone is incredibly long-lived and durable, see the Pantheon in Rome.
That requires massively overbuilding the concrete structure, and many of the things we mold concrete into simply would not be feasible in unreinforced concrete, it's only strong in compression.
Plus the Pantheon and friends are good examples of survivor bias, for the on Pantheon there are hundreds of insulae which didn't survive.
This is a total misunderstanding of survivorship bias. It would be like encountering a 1,000 year old man and attributing his age to merely survivor bias rather than investigating whether it has something to do with the magical beans he ate.
That requires massively overbuilding the concrete structure, and many of the things we mold concrete into simply would not be feasible in unreinforced concrete, it's only strong in compression.
Plus the Pantheon and friends are good examples of survivor bias, for the on Pantheon there are hundreds of insulae which didn't survive.