Even if a 4 lane black road were completed through the Tenere in Niger this afternoon, I would say it would only be 3 years before the trucks were driving down the inter-dune corridors on the sand sheet again - maybe next to the road or maybe with the road underneath the corridor.
Niger doesn't have the capacity to maintain a remote road in a place where the sand flux is so high. It doesn't seem to have the capacity to maintain a road into the capital, Niamey. When the Uranium road turns off south to the coast, the road going on from east to west to the capital turns into a mess.
And Libya blows hot and cold on whether it wants traffic from the south in any case. Not so long ago, Libya was rounding up and flying out the migrants from south of the Sahara.