Afghanistan is a landlocked country on the other side of the planet, the soldiers didn't grow up with knowledge of the terrain, they had no knowledge of the language, culture, customs or social networks, no one locally (with few exceptions) wanted them there, and crucially they only lost once they left, and when they left, there were no penalties for the people who started the war; no US politicians were in any danger whether the war was won or lost, no land was lost, and no truly important geopolitical goals failed.

On the flip side in any domestic insurrection, the soldiers know the terrain, language, customs and culture of the people, the supply lines are nothing (rather than having to airlift materiel and people thousands of miles, you drive them on regular roads), the infrastructure supports espionage, most people support the regime and will collaborate to return to stability (since they voted for it), the regime never leaves (you can leave Afghanistan, you can't leave your own country or it ceases to be a country), and if you lose, you lose territory and/or politicians run the risk of violence. The stakes are why these comparisons are never relevant.

This isn't really accurate. The Northern Alliance entered into an agreement with the US to secure the country. An insurgency sprang up and we fought it for 20 years before giving up. Since this is now after the fact, we can safely say the Taliban ran the insurgency the whole time.

The Taliban are a military and political group compromised of an ethnic minority in Afghanistan. It's not even that the US lost to "goat herders with guns". We failed to secure a small country against a well organized, armed minority.

To be fair, those "goat herders" were previously trained and armed by the US to fight Russian forces, so it's not quite an apples-to-apples comparison

Pretty sure Iranians with 3D printed guns would not be able to kick their own army out of Iran.

But could they do the same to goat herders with bigger guns, drones, bombs, etc?

Let's do some napkin math: Iran has about 94 million people. Iran's IRGC alone has a personnel count of 125.000 [1], of which about 2-5000 are estimated to be the elite of the elite ("Quds Force"). Together with the Basij (anywhere from 100-600k) that alone is a sufficient amount of force. And on top of that come maybe 400-500k of the regular Iranian Armed Forces [2], as well as about 260k active police+100k police reservists.

So, if one sees the whole of IRGC plus Basij as the "commandos", they alone form an active elite of about 0.5%, if one sees the entirety of the military+police we're looking at easily 2-3 million units, so up to 2%.

[1] https://en.wikipedia.org/wiki/Islamic_Revolutionary_Guard_Co...

[2] https://en.wikipedia.org/wiki/Islamic_Republic_of_Iran_Armed...