What would Afghanistan over the last 20+ years have looked like without 9/11 or a comparable similar large-scale terrorist attack on the US?
Well, the Taliban politely thank Osama for killing Ahmad Shah Massoud and his other help, and then politely tell him that he has worn out his welcome, and should leave in honor a year after Massoud's death.
The Taliban and Al-Qaeda have diametrically different world views and incompatible religious doctrines. The Taliban tolerated OBL as long as they did because he was providing shock troops against the Northern Alliance and helping to rebuild the nation. So in 2002, OBL goes to Pakistan and later to Iraq.
The US still invades Iraq as that was already in the works when Bush entered office. 9/11 and the Enron Scandal delayed things as Bush felt the blind need for revenge instead of a far cheaper and more effective solution, and Enron would have been the primary contractor for Iraq's energy sector to avoid the appearance of impropriety if Halliburton was. Its why the Enron Meetings with Cheney are still under wraps for the most part. OBL winds up making that his new place of business.
But as for Afghanistan. The Taliban begin the process of encircling the Panjshir Valley via methodical advances backed by a trickle of support from Pakistan. The Northern Alliance is slowly ground down and the Iranians resort to air drops as the NA loses airfields. But once the Taliban takes Taluqan, Faizabad, and Parun, the NA is effectively finished.
By 2006, Afghanistan is firmly under Taliban control and is rebuilt in their image and neither a friend or enemy of anyone. Mullah Omar allows radios, but no smart phones, or TVs outside of trusted security services. Its military consists of a relatively hi-tech air arm and a ragged Army with little uniformity and wielding AKs with worn out barrels (smoothbores basically).
There is no population boom at least for a while, and selective pressure results in women with the best child bearing attributes and disease resistance surviving to pass on their genes as largely untrained midwives take over child birth procedures. Without the need to hide, Mullah Omar stays living to present day assuming no other issues and no major changes occur as he ensures only those 100% committed to his vision get any power.
City wise, their is no skyscraper buildings at least not as we think of them. Instead their will be more midrise buildings in the 5 to 15 storey range made of concrete. Farming will be slowly mechanized, but largely remain as it had been for centuries.
Any real change will be 2 to 3 generations in coming and only after thorough vetting and control by the Ulema. Female literacy will largely be non-existent, and female participation in the economy will be relegated to farm work, a few female medical personnel, and a few female police officers married to male police officers. Most women will be confined to unpaid domestic work in homes.