> Drop a brick on copper pipe, and it will dent because it is more ductile.
> Drop a brick on iron pipe, which is stiffer but more brittle, and it will
> fracture from the impact.

A brick heavy enough to fracture an iron pipe will crush a copper pipe of equal dimensions.

Vibrate both pipes together, and the copper pipe will fail first.

Uniformly load both pipes together, and the copper pipe will deflect more, and be the first to yield.

As I said, do not make the mistake of concluding that stiffer cannot mean stronger.

> The steel-to-copper comparison is more of an apples-to-oranges comparison
> because the materials are different.

Irrelivant. It was an accurate demonstration of the falicy of the argument that stronger is inherently opposite of stiffer.