I feel like this definitely something younger people don’t understand. The extent to which everything human-made needs constant effort to keep it from decaying. They see a world already built up and functioning and don’t realize the monumental effort that requires.

The first time I built anything to survive outside (a ramp to a shed), I learned this the hard way.

Even with a decent amount of planning for the elements, it lasted 3 years. It really makes one appreciate how special it is that this lump of flesh might survive 70 or 80 years.

Your lump of flesh is constantly replacing and repairing it's components

and why can’t civil structures do the same?

They can and should. That's the sign of a happening place. When reconstruction and replacement stops, it's a sign of decline

That is true as well for democracy.