And so you do know think that the reason for going to Afghanistan in 2001 was really to fight terrorism? Now that's cute.
Remember when someone typed something along the lines of "The reason WE WERE FUCKING TOLD for the invasion" was driving out Al Qaeda? Oh, right, that was me. Maybe you missed some fucking nuance there, but I made clear that this was THE OFFICAL Reason. And, in point of fact, it turns out that many Americans, including in high policy making positions, actually did believe that. The problem is that Americans, especially the ones in power, believe stupid shit all the time.
On the one hand, that is where Bin Laden packed up and moved to after the Saudis cracked down on inconvenient Wahhabi extremists. And by "inconvenient" I mean the ones who were questioning official Saudi policy, not the ones running the state schools and religious bureaus. Bin Laden had connections there from fighting the Soviets with the blessing of the CIA and some indirect American training and support.
With the Bush administration closely connected to the Saudi government and business elites, we obviously couldn't go after the government that created and supported itself with the Wahhabist establishment. So it was obvious that we needed to invade Afghanistan. And Iran.
The US could have carried out a short, limited operation to reduce Al Qaeda's bases and cut off their support. But instead, we dragged NATO into it and decided to stay and "fix" the place. So I really do think the Bush administration thought they could end the threat there and build up the local government, but they were idiots and they made a typical American mistake: they failed to articulate a clear, concise, limited goal before starting a military operation. If you don't set a goal, you can never achieve them, and you never know when the mission is over. It creeps into nation-building, which defaults to installing a friendly but corrupt and ineffective regime.
It's true that the USA never had much experience with terrorist organisations in their homeland. There were only few incidents which ever happened. This means they also had not so much own knowledge about how to really fight terorrism at home.
You think the US doesn't have terrorists? That's fucking cute. We have the KKK, the Sovereign Citizens, the John Birch Society, the Birch John Society (they demand a return to wooden outhouses), a host of Skinheads, Proud Boys, the 3%, the Tea Party, Operation Rescue, and the LAPD. We are awash with terrorists, and there are regular terror attacks in the US every year. The difference with 9/11 and the earlier Trade Center bombings was that the terrorists were (foreign) and (brown). That made them different from the background noise of domestic terrorism that is daily fucking life in the US. The Iroquois still consider George Fucking Washington a terrorist for his campaigns in the French and Indian War. We have a long history of terrorists, and I still think that John Brown was right, but he was a terrorist.
Going to Afghanistan was mostly about one thing in reality, like always when the USA invade somewhere: access to oil and natural gas.
This is the same really stupid bullshit I keep hearing from people who don't like to think too much but don't like American foreign policy. Including a bunch of sincere but often shallow Americans. It gives one stupid magic fucking bullet to explain everything, and it is wrong far more often than it is right.
The first thing to get out of the way is that Americans and many Europeans like to point out that building a central government in Afghanistan failed because people there are "tribal." That smug assurance brings with it an unstated assumption that we are not. Guess what, many Americans are (and in the wake of the pandemic, it is clear that trialists against people who see the world as a community is at the heart of America's current political divide). And the worst American tribe isn't the petrochemical industry (they are in the top 5). The worst is the fucking Fundamentalists. And the Bush and Trump administrations were awash in them.
Remember one of our Generals making a comment that we would win because "our God is bigger than their God"? They fucking really believe this shit. They see a clash of cultures, with Christians at the top and godless Muslims as a primary threat (except the ones we are in business with). People who formulated American policy really were this stupid, and they appealed to even more idiotic followers who boil most of the world down to US (American and a few countries when they behave) and Them. "US' is Christian and Good. Them isn't. Which is letting the Republicans rehabilitate Russia since Putin has elevated the Orthodox Church there to what many American denominations want to be.
So the first reaction after 9/11 was tribal. In the immediate aftermath of the attack, many people who usually know better, who act globally instead of tribally, hopped on board for a short time. I remember one of the speakers at the hastily organized vigil on 9/11 at the University I was working at spent most of their time blaming Islam, Jews, and Buddhists for the attack without a fucking clue what the actual causes were. It was a tribal reaction to an outside attack, and the Bush administration used that anger to appease fundamentalists, their business interests, and their Saudi and other Arab partners. After the shit hit the fan, opportunists swept in to make money where they could off of the chaos, from military contractors to weapon suppliers to looting oil, gas, antiques, drugs, and anything else they could turn a profit from.
Where the petrochemical industry has made money, it has been opportunistic and after the fact, driven largely by their investment in American politicians. They don't have a board with a list of places the US needs to invade, they have a list of places they can make money and the connections to use global events to turn a profit.