To stay as long as we have, is to ignore geography and history. This geography is uncontrollable and of little value. Afghanistan is covered with mountains and only 12% of its land is arable. It's also landlocked and for centuries has been overrun by hordes passing back and forth through Asia. The current social structure is tribal because the geography cannot support a higher socio-economic system. In the classical anthropological model, clans become tribes which become agrarian societies and then industrial states. It can’t happen everywhere because of geography and other factors, but Afghanistan was never in the model – it’s stuck in the Neolithic Age.
We ignored history there too. The English fought two Afghanistan Wars in the nineteenth century and lost an entire army in the first. The Russians fought the Afghans from 1979-92 and gave up. We should know that the same can happen to us if we continue to ingore the history.