The Taliban have now seized central Kabul.
With literally US$ Trillions spent and many lives lost the US, UK, Australia and other countries that defended Afghanistan for 20 years are running out of time to evacuate thousands of Afghans and foreigners from Kabul Airport. Hopefully US intelligence has paid off the Taliban NOT to shoot down (with shoulder fired missiles) passenger planes leaving the airport.
The Taliban were ousted by Western forces 20 years ago as a central plank of the Post 9/11 War on Terror. Ousting the Taliban in 2001 did reduce terrorism in the West but then Western defence of Afghanistan became self-justifying.
The Afghan Government, its armed forces and police were always dependent on Western money and military support. Western forces usually led and did the fighting, with Afghan interpreters helping.
Now Afghanistan's President, long seen as a Western lackey, has fled. He and previous Afghan presidents was usually seen as merely "Mayors of Kabul" rather than legitimate national leaders.
Afghanistan was never a unified nation fighting for an attempted transplanted Western Democracy. So there was never a cohesive national Afghan Army to hold back the Taliban, al Qaeda (AQ) or Islamic State (IS).
Now Afghanistan may return to being an AQ terrorist training school with a renewal of lessons on how to make bombs to blow up parts of Western cities, trains, buses and aircraft. IS may grow and train in Afghanistan as well.
One difference is that Russia is in a stronger position than in 2001 to block "Talibanism" getting into the "stans" (like Turkmenistan and Uzbekistan) which border northern Afghanistan. China also has power and a reason to block Talibanism from infecting Tajikistan (sitting between Afghanistan and Western China) and then radicalizing Chinese Muslims.
In the next 12 months or less - if there are new Afghanistan linked terrorist outrages in the West at a minimum there will be US drone and cruise missile strikes on terrorist training camps in Afghanistan. After the US 2024 Presidential Election there may be a return of US (and therefore UK and Australian) forces to Afghanistan.