Today the average afghani is a starving peasant unable to sustain themself.
As a result, the richer nations are spending our tax dollars to buy food and fly it around the world (not cheap) to feed them.
And after they are fed, nothing has changed, they are still indigent and starving.
That condition can continue indefinitly.
On the other hand, our government can make redevelopent guarantees, so banks can make redevelopment loans. Corporations go in to rebuild, based on those loans.
Once Afghanis are employed by those corporations, they become consumers, buying our goods and services from our corporations, which in turn pays off those loans. At least that's the way it worked with Europe after WW2.
Yes there are problems with this scheme, as in Japan. The tendency is we get soft and rest on our laurels, and the country we rebuilt then passes us and becomes a competitor. But even then it's all good; our economies are so entwined, the Japanese would never think of bombing us again. We're their biggest market.
A starving Afghanistan has nothing to loose by being violent.
A prosperous Afghanistan has an incentive to be peacefull.