A theory as good as any other. I do think we lost track that most Afghans owe their loyalty to their tribe, not some leader of another tribe. It also didn't help that the Afghan government was very corrupt. That a lot of the troops the government of Afghan said they had was only on paper although we were paying for those, what I call ghost troops.
Afghanistan has always been a tribal country. Not a country as we envision a country to be. Think back to the different tribes of the American Indian. They were never unified as one. The same for the 18 different tribes of Afghanistan.
If I remember right, the Taliban are from the Pashtun tribal area of Southern Afghanistan which the Pastuni tribes united under the name Taliban. They basically conquered the Mujahideen warlords who drove out the USSR and in the late 90's captured or controlled most of the land area of Afghanistan except the northern portion which fell under the 13 tribe Northern Alliance.
I think the bottom line is in reality there never has been a central government as we know it for Afghanistan. Just different tribes ruling over their own area of Afghanistan until we came in and began nation building. Much like the American Indian who never had a central government either, just tribal governments if government is the right word.