Then there's the factor that, in the times such a bridge was built, having it collapse would've been a larger catastrophy than today. Today, we can quickly fix things and build another. In the old times, that bridge might've been the only bridge making trade at all possible and it might've taken years to stack stones.
An unnecessarily strong castle takes you more time and resources to build.
A slightly too weak castle means you die, your family dies, and you lose all wealth and power.
> An unnecessarily strong castle takes you more time and resources to build.
> A slightly too weak castle means you die, your family dies, and you lose all wealth and power.
You're really glossing over a lot of important concerns here. There are many, many ways to lose all your wealth and power, and lots of them might have been avoided if you'd had a few more spare resources.
Actually one of the reasons big infrastructure projects were undertaken in the middle ages was just the opposite: to provide a reason for an economy to exist. Something for the population to do.
Most spectacularly this is seen in Cathedrals, but castles, certainly some castles, definitely show this. I would argue pretty much everything the Romans built is more than a little overspecced, certainly at construction time (do you really need 3 story POOLS, meaning pool on -1, pool on ground floor, pool on first floor, pool on 2nd floor buildings ? Yes the higher ones were apparently rented out to very rich Romans, or more often provided as favors to them, so there was some function, but ... come on. They were constructed to mostly look very convincingly to be 3 story pools without actually being that. Despite that, none of the buildings survived for very long. But "over the top" can be said about many Roman structures, from the Pantheon to the Aya Sofia)
So having an unnecessarily big infrastructure project has it's own advantages that actually increase your odds of survival, and that didn't start with the space race.
> one of the reasons big infrastructure projects were undertaken in the middle ages was just the opposite: to provide a reason for an economy to exist. Something for the population to do.
This isn't really compatible with anything I know about the middle ages. Can you show someone of the time writing or otherwise demonstrating that he doesn't want the cathedral, but he's afraid of what the population will get up to if they're left idle?
An unnecessarily strong castle takes you more time and resources to build.
A slightly too weak castle means you die, your family dies, and you lose all wealth and power.