> too much water, not enough cement, etc.

I wanted to mention that Concrete is far more complex and regional than folks might imagine. The quality of gravel and sand, local impurities - these all contribute massively. It's probably best to think of it like a wine's terroir - except, unlike a bottle of wine, it's prohibitively expensive to ship both the components and the finalized mixture to different areas. If a region's limestone has a massive clay impurity then it may simply be unsuitable for large structures or require extensive filtering to the point of being uneconomical.

It's important to be aware of just how much the local geological mix can impact the viability of building with concrete because while theoretically we could use perfect concrete for every project - at that point most projects would simply be too expensive to consider undertaking. There is a very large field of engineering around establishing the realism required in settling for what you've got for the price you can afford in. It can absolutely mean that the materials required to build a high rise in Philly might be priced starkly differently from the same structure planned in Milan even with adjustments for the labor impact on pricing.