It's very easy to blame the USA, and the USA alone, for the problems in that area. They did indeed take their usual, facile 'my enemy's enemy is my friend' view of the Afghan resistance to the Russian invasion of the country, arming the Mujihadeen while completely failing to recognise or understand the ideology behind Islamic militancy.
But Afghanistan was a problem long before the Soviet invasion, as we found out in the mid 19th century. Almost constant civil wars and inter-necine fighting have taken place there since the mid 18th century. As
@ZenHalfTimeCrock says in his post, there are many factors that led to the current instability. The rise of militant Islam pre-dated 9/11 (probably starting in the 1920's) and the subsequent actions that resulted from that. The Soviet invasion of Afghanistan probably came at the perfect time for the Jihadi movement, as it gave them a proper battleground for the first time.
Pakistan effectively created the Taliban (although there are at least two or three distinct groupings), with significant input from Saudi Arabia and Iran. Without Pakistan's support, the Taliban could simply not have survived.
Afghanistan isn't suffering from a natural disaster, like drought or flooding, currently, which is causing the reported mass starvation. If the Taliban (or anyone else) wants power, then that's fine but they have to exercise it responsibly, for the good of the people they represent and show that they're capable of running an economy and all the institutions that a modern country needs.