Cute saying, but an aircraft doesn't really share this property. You can make a bridge or building stronger by just adding more stuff. Many pyramids and stone bridges have held up admirably even after thousands of years.
You can't make a better aircraft by just adding more stuff. Very soon, it becomes incapable of its primary purpose.
It turns out that if you take some task that is incredibly hard and inherently complex and performed by a very large number of extremely qualified and smart people near the limits of human experience, and you want to do that task in a better way it isn't going to boil down to something simple or obvious.
In fact, if the US political process is so broken, why is it the only process that ends up with space shuttles sitting in hangers? It's certainly not perfect, but since nobody can point to a political process that results in better space shuttles I don't see any evidence that humans have so far developed a better political process if you are measuring it in units of 'space shuttle reliability'.
TL;DR version:
The original design of the space shuttle was vastly smaller and simpler, but during the cold war the only way you could get something funded was to have a military dual use. So the Department of Defense offered NASA funding so long as they redesign the entire space shuttle to be able to capture and return Soviet satellites to the US -- a task that it never performed -- which required the design to be massively compromised.
The design of those shuttles lacked the flaw that contributed to the Challenger tragedy.
So, what was the engineering reason for implementing a US design requiring o-rings?
I’m pretty sure there were plenty of flaws that would have shown up if Buran had flown 100+ real orbital missions.
Doing things that are “incredibly hard and inherently complex” and also unnecessary and dangerous is idiotic. Things like building and flying a space shuttle rather than a normal space capsule. Especially when human lives are at stake.
Holy crap, that truck in oncoming traffic just barely avoided hitting us head on!
If that driver hadn't adjusted their speed appropriately for the road conditions and planned on switching lanes a quarter mile back we'd all be goners, bro.
I once heard it said that any reasonably smart person can build a bridge that doesn't collapse. It takes an engineer to build a bridge that just barely doesn't collapse, by an acceptable safety margin that still provides economy. So yes; any unforeseen failure exists because of that tradeoff.
The counterexample you name, the Space Shuttle, is just a series of fundamental mistakes compounded together--a boondoggle machine designed for a dozen different mission profiles, most of which never happened, and introduced serious regressions in survivability and launch escape compared to Apollo.