No - it's actually local variance in materials coupled with the difficulty in moving materials between markets economically. Some areas just have better suited limestone or gravel or sand and can afford to build resilient structures for a fraction of the price that it'd cost in other areas.

This issue here is mainly that it's very expensive to ship all the components of a Concrete in the volume necessary in an economical manner. Some areas of the world just lost the lottery when it comes to having resilient building materials.

Corruption absolutely is an issue as well - I don't mean to downplay it - but even if we remove it as a factor there are just a lot of variables involved in making a reliable Concrete... finding a good mix is an artform and if, for instance, your limestone quary suddenly hits a more clay-laden amalgamation then your Concrete that was reliably lasting for three decades under certain conditions might suddenly lose a decade off the expected lifetime. That change in material quality can also be difficult to detect so there are real quality assurance issues in Concrete mixtures outside of just corruption and cutting corners.