alt Hacker NewsSteel has almost always (as in 99.99...% of the time) delivered to our expectations based on our understanding of it.
The cases where we built something out of steel and it failed are _massively_ outnumbered by the instances where we used it where/when suitable. If we built something in steel and it failed/someone died we stopped doing that pretty soon after.
This is partly due to having a safety factor: i.e. using twice as much steel as you think you need.
Understanding means knowing the limits of your own understanding, and building in safeguards.