If this hypothetical road is so important to the people living on it, they can always simply choose the free enterprise approach and maintain it themselves.
The point the Iowa DOT is making isn't that there must be less roads but that government built roads have gotten way out of whack and there is far more asphalt per person than we could ever hope to afford. Nothing stops a few industrious folks from stepping up and maintaining their own roads.
If the people living on a road can't afford to keep it upgraded, then it's a sign from the universe that they can't really afford the lifestyle they are trying to live and they have been subsidized for years. There are lots of options
- gravel roads cost a tiny fraction of hardtop roads
- hiking trails cost even less