It doesn't matter whether the Taliban or any other Islamic faction ultimately takes charge of Afghanistan. Anywhere you have an Islamic government, you have a terrorist manufacturing center. It's true of Saudi Arabia, Pakistan, Iran, Syria, Kuwait, Iraq, Somalia, Yemen, Libya, Indonesia, Comoros, Sudan, Qatar, Morrocco, Chad, Brunei, Niger, et cetera, et cetera.
The western nations sit by in utter denial that "Islam" is at war with not only the west, but the non-Islamic world in general.
In centuries past, Islam would send armies to try and conquer the non-Islamic nations. Try as they may, they could not successfully win against the better equipped and led armies they were up against. Fast forward to the twentieth century and they have finally found the way to destroy the infidel enemy......."from within." Simply send millions of fighting aged mostly men, into the infidel nations, unarmed, but with the intention to destroy it from within, by growing numbers. An army, without weapons, gradually destroying the infidel nations by growing numbers from within. Eventually, success. Once the numbers are there, simply do as was done in Lebanon. The people killing infidels are simply the armed elements of Islam. The war continues.