Both. My opinion, based on my personal experience which is only a very limited view, is that Afghanistan is like most other countries, most of the time, in one key respect: 80-90% of the people just want to keep their heads down and get on with their lives.
The country was given a chance for the majority to change the other 20%, and didn’t take it. This majority didn’t want the Taliban and the future they were offering, but as a whole, just kind of ignored it and didn’t really bother to prevent their resurgence, leaving it all up to the various foreign countries and their forces to sort out. If they had have committed, and in conjunction with the advantages given by the security and assistance provided, the Taliban, et al, would have found a very hostile environment and likely couldn’t have operated or existed for long. Perhaps there are people now who regret taking such a passive approach, but it’s too late now. I don’t ‘blame’ them at all, I’m sure I’d be the same. But like everything, decisions (or inactions) mostly have consequences.
Quite similar parallels to Vietnam in the 60s/70s to some respect.
There is an argument to be made that their culture and resulting indoctrination made this leap very difficult, and I’d agree with that. But of course, there are examples in history where other countries/peoples have managed to do just that; often without the backing of a huge multi-national force and diplomatic effort behind it, either.
Anyway, that’s a very simplistic and narrow view for a very complex issue. But this is only a post on Mumsnet, after all.