I wouldn't exactly call the US flourishing. White males in the US have seen life expectancy decline, and our democracy is considered "flawed" by most observer groups.
There are countries in the world whose way of life has persisted relatively unchanged for hundreds or even thousands of years, in comparison. Maybe they understand things about sustainability that America does not. Maybe they don't need western nations coming in and "fixing" them.
So instead of 'fixing' Afghanistan, the USA needs to be 'fixed'
by Afghanistan? Not to paint myself as any kind of expert when I'm not, but I do happen to live in the metro area that has the second largest Afghan population in the entire USA, and my neighborhood in particular is ground zero for that population (it's also where a lot of car dealerships and garages are, and around here those businesses have names like Karim Auto and Azadi Brothers; that ought to shut up people who believe that 'they' simply can't/don't want to integrate into wider society, yet it never seems to...), and while I would say that I personally think this has fixed my neighborhood in some ways (for example, there are way more Afghan restaurants within walking distance than McDonalds' or Starbucks', which is nothing but a positive in my eyes), it hasn't magically transformed it into an island of sustainability and long lifespans in an otherwise collapsing society.
I don't want to seem like I'm picking on you personally, but when I read about how so-and-so obviously understand things about what it means to
really blahblahblah that we do not with our modern ways and so on, it just seems like a retread of the 'noble savage' myth that is frankly really pretty gross. It may not be the first thing that comes to mind when most people think of stereotypes about 'the East' held by people in the West, but it's no less othering, exoticizing, etc. ('Magical Pashtoon'-ing? Hahaha....I don't know) than the more obviously negative characterizations are.
The thing about Afghanistan is that lifestyle was not popular outside of Kabul
That's true of absolutely
every type of society, though. The pre-'revolutionary' (read: pre-communist) nightclub scene of Ethiopia in the waning days of the Ethiopian monarchy in the late 1960s-early 1970s, for instance, was really only fully enjoyed by a very small class of economic, cultural, and political elites who could already afford to not just live in the capital, but also do things like spend money on records (an anecdote related by Ethiopian music specialist Francis Falceto about
Getatchew Kassa's electrifying 'modern' version of the Ethiopian standard "Tezeta" being the biggest smash hit of its time while selling something on the order of at most
maybe a few thousand copies is probably illustrative of how small this elite really was), go to nightclubs to dance and party all night, etc. That entire world had nothing to do with the reality of life outside of the capital in the villages, as the famines that periodically decimated the countryside both before and after this small window of of time showed in the most brutal way possible. And of course Ethiopia was never an Islamic society, nor was it ever successfully colonized by anyone, so...yeah, what are you talking about?
Last time I checked, the lifestyles of those in places like San Francisco or Los Angeles are not popular with people in more rural and conservative places like Tracy, California (in the San Joaquin valley), which is instead known for things like stabbing hippies (at Altamont) and being home to a branch of the American Nazi Party in the uncomfortably recent past (1960s-70s; according to Wikipedia, the city's neo-nazis relocated to Oroville after media reports shined too bright a light on their existence in the late 1970s, which...good?). So at level, the characterization you've given of Kabul v. the rest of Afghanistan even holds true in the USA.
You can't hold together a country with the consent of only one group of people, and where the government is seen as evil or corupt. You can't buy somebody off who believes their culture is being colonized and subverted.
Tell that to the Arabizing regimes of North Africa. Algeria doesn't appear to be going anywhere anytime soon, despite the periodic Berber revolts for more cultural recognition and rights, the murder of prominent Kabyle voices (like singer and secularist Matoub Lounes, for one example). Ditto Morocco, where Imazighen ('Berber' is pejorative) share an even larger percentage of the population pie. (Libya is something of a special case, thanks to particularly recent western meddling that largely has nothing to do with demographics, combined with the Qaddafi regime's special brand of craziness which made western meddling seem reasonable to some people, if only by comparison.)
Plenty of governments as well as individual leaders (to the extent that they are separable, which is not always the case) get by for a very long time by appeasing rather small groups of people precisely
because they are corrupt, and this is how the game of politics is meant to be played when the leaders' real concern is to hold on to power rather than to behave as a 'good' leader/government should (that is to say, in the real world, where this is uniformly the case across all forms of government the world over). I'd recommend reading the book
The Dictator's Handbook: Why Bad Behavior is Almost Always Good Politics by Bruce Bueno de Mesquita and Alastair Smith (PublicAffairs, 2012), if you want an accessible explanation of why this is, despite the fact that it feels like it should be a recipe for failure (because isn't being terrible and unresponsive to your peoples' plight a one-way ticket to being hung upside-down and having your corpse humiliated, a la Mussolini?). The book is also available on Audible, if you prefer to listen to books in audio format.