I agree about tribal structure being more feasible for them, but I strongly disagree about them being anything other than an extremist, anti-technology, anti-women, anti-democratic gang of thugs who oppose ANY idea that disagrees with their religious nuttery. Their base are rural tribes with limited access to technology - that part makes them primitive, right along with their rejection of modern democratic liberalism (not so much a political stance as it is culturally embedded.)
Here's the part I do NOT "like'. It's not condescension. It's opposition to barbarism, including our own.
Taliban publicly execute woman
How would you distinguish the motivation of one of these members of "rural tribes with limited access to technology" (a description I am not sure is wholly accurate) from that of European and US Muslims who went to Syria to join Daesh as a result of their slick online recruitment campaigns?
It's more, I think, a case of how people want to live -- lots of people in Afghanistan, particularly up in the hills, live in small rural settlements, where people farm and hunt, and raise sheep and livestock, and feud and smuggle and grow opium, just as they always have done.
Clan loyalties in that part of the world run very deep, since they're really family and community loyalties, since clans there, as far as I can make out, are primarily a method to making sure family land-holdings don't get broken up, while at the same time preventing intermarriage between blood relatives, since there really isn't a great deal of government outside of the cities -- it's up to you and your cousins, and everyone's inlaws, to look after each other.
People who don't like that kind of life leave for the cities, or to work or study abroad, just they do in the US, though generally maintaining close contact with the folks back home. People who do like it stay there.
It's not, I think, that people there particularly like the Taliban (though their social conservatism is probably shared by many of the village and tribal elders) but more that the Taliban are the only group capable of forming a government at the moment, and the provincial governors, and the tribal and village elders, would rather go along with them for the time being than risk an all-out civil war.