The approach seems to be that transient patrols, haphazardly driving around and visiting villages in giant bomb proof robot trucks, is a substitute for thousands of years old strategies of taking, holding and controlling territory. There's no front lines in the kind of conflict because that's how the new strategy has defined the conflict. The last time a modern military in a major conflict actually took and held ground was probably the Korean War. After that it was endless insurgencies or hit-win-withdraw like in the first Iraq war.
This is opposed to the Taliban which can comfortably move into a village and live there 24/7, becoming "the villagers" as much as anybody who was there before. A robot truck driving up and asking "where are the non-villagers, where are the bad guys?" will get no answer because everybody is a villager, and the guy making bombs in the afternoons is a village elder the rest of the day. There are no bad guys.
Afghanistan isn't a failed state, it's an anti-state, its borders are a reflection of the borders of its neighbors -- extending only so far as they cared to and stopping when the terrain became too difficult to bother. Within this zone are several city-states and otherwise large stretches of lawless territory connected, but not held together, by a network of smugglers and local warlords. The coalition controls none of it save for perhaps the city-state of Kabul.
Of course the ability to take and control territory means lots and lots of manpower, which runs contrary to modern military thinking. This forces military leadership into a state of sustained denial that this or that alternate approach will be the one that opens up the opportunity for Afghanistan to develop into a real state. They're flummoxed that it isn't happening.
But there's sadly only one proven way to accomplish this goal, take, hold and control territory. Put in place a carefully controlled puppet dictator or similar for a couple decades, one who will build up strong institutions of government and industry. Then once these things are in place, kill him or his dynastic line off (or have a quiet democratic revolution) and have the people assume ownership of these institutions and industries. Sure if the timing of these things is off it fucks up and we end up with Iran. But if the timing is good we end up with South Korea.