Since you don’t realize there are very different processes going on between surface damage and structural damage to the foundations, I’ll assume you’re just repeating the internet and don’t actually know anything about building roads.

The top layer isnt part of what is considered the structural component. It’s also extremely unfair to compare it to roman roads, because asphalt and natural stone have completely different properties and qualities. But more importantly, it doesn’t take engineering skill to build the top layer, every civilisation ever has built roads by just putting down stones, and those roads are all gone. The skill in building roads is in the foundational layers, they’re what makes your roads last.

And there are many modern roads in the world that are a meter of sand, a 50cm of aggregate, 30 to 50cm of sand asphalt and then a lower layer of 12 centimeters of underlayer asphalt followed by anything from 3.5 to 10 cm of surface layer depending on the type used. Those first few centimeters will of course need replacing every 5 to 10 years, but the road construction underneath is 80 years old and will easily last another 200 (the models will usually show “>100”)taking into account the wildest growth of traffic

But we stopped building like that, because we tend to not want roads to be in the same spot for 300 years. The romans did, because not only did their traffic needs not visibly change (can’t blame them for not having modern counting systems built into the road), they also had no concept of things like that. People would always need to travel from Rome to the outer cities. They would always need to walk to Gaul. That would never change in their worldview. So they obviously built to last forever.

We don’t. We have a very clear knowledge that we’re improving constantly and that we will probably change things around a few times before the end of the century.