A minority of the Taliban went to Pakistan or came from Pakistan which follows a diametrically opposed Deobandi School of thought, the bulk remained in country, fighting in the Spring-Summer, going home for Winter. Also the US and Afghan Government routinely targeted the Civilian Population and are responsible for the bulk of civilian deaths.
I fully agree that the US made a real mess of their operartions, I think because they were never really thinking beyond the initial 'victory' and ignoring the hard work of putting a decent system in place. However they won so quickly and easily in large part because the Taliban were destested for their brutality and incompetence.
Also the Taliban captured the Country intact in 21, not their fault the IRA Government were corrupt douchebags. If half the country starves its because the IRA government stole all the money and the "West" refused to return it, making all deaths on IRA and the "West" not them.
They captured a mess they had in part created by so many attacks on civilians and infrastructure and continued to command the problem by vindictive persecutions of both formal government military and the many groups they refuse to accept as people. The corruption of the previous regime played a part in this but the blame is largely on the Taliban for their continued excesses and lying which keeps the country in terror.
The issue that would make a difference would be western aid but why should the west send large funds to a regime that's likely to pocket it themselves and pretty certain not to pass it onto those most in need because they want them dead.
Prior rule, the country was already a wasteland due to the warlords, they simply restored order and were in the process of rebuilding the nation. If Bush had been smarter, some cash under the table, and a few knives in the dark would have sufficed for 9/11. Instead he got the US embroiled in a world wide war that is now decisively lost and the US is now broken.
Prior to the initial Taliban conquest the country was in a mess due to civil war, Soviet occupation and then the warlords. They didn't do much to rebuild, being more interested in their deranged ideas of misrule until they then decided to support bin Laden's international terrorism.
US was 1/3 loyalist, 1/3 neutral, and 1/3 rebel in 1776, the war was brutal, but the minority won by force of arms and despite losing more battles than they won. The will of the majority did not matter because the rebels had their shit together and the Loyalists and the motherland did not.
The Reds were outnumbered by the Whites in the Russian Civil War and the bulk of the population was neutral. Reds won, the popular will did not matter.
Same in China, Vietnam, et al.
Some merit in your 1st comment although of course your ignoring that the bulk of British effort was engaged against the assorted great powers who aided the rebels.
I think the Reds, for all their incompetence actually had more support than the Whites because the latter were seen as associated with the old autocratic regime that had caused so much death and suffering. As such many decided, quite probably wrongly in hindsight, that the Reds were the less worst of the options.
I've already pointed out that your wrong in the case of Nazi Germany [could also say Imperial Germany], Imperial Japan and the USSR.
Victory is all the justification needed. Thus has it been and always will be. Your argument is based on a false premise that doesn't hold water.
For the fanatic but they never look to building a lasting state because their only interested in power and ego and their incapable of looking beyond that. Hence why 'states' established by groups such as that tend to be transient and fragile.