“IAC, you are talking about tactics. I am talking about politics.”
No, you are talking about tactics - building roads to move masses of soldiers around the country.(like the loser Russians did)
I, not you, are talking about politics, particularly the domestic politics that wins all asymetrical insurgency/counter-insurgency campaigns - getting the population to fight and die for your side.
Until the Afghan army is massive enough, well trained enough and well supplied enough, their sons are not the majority of Afghan soldiers getting killed. There are more Afghan Taliban soldiers getting killed and their families out number the families of Afghan soldiers killed by them. Until those numbers are reversed, the Taliban have more of the population seeing them as the nationalists and the coalition forces simply as the foreigners.
The Afghan government does not need more roads. It needs more Afghan soldiers and more of them doing the fighting and dying. Then those soldiers families will provide the change in the population that will support defeat of the Taliban. Until then, the rest are mere tactics that in centuries of fighting have never won anything in Afghanistan.
Once the nation has much much greater security, the security that must precede good commerce, there will be plenty of time and resources to build lots of roads for commerce.
The “country “actually a bunch of places side by side. A system of roads would tie the pieces to gather and enable Kabul to extend its authority into the mountains and allow trade to move more smoothly from place to place. As for moving “masses” of troops, you don’t need to move more than a few battalions in order to bring enough force to bear. Roads would also allow police and other services to reach the people.