I honestly think a big problem was the US civilians were expecting Desert Storm, while signing up for South Korea.
I remember being an E4 on CQ (24 hour duty) when we rolled into Iraq in 2003. Watching it start live I was talking with the NCO that was also on duty and we were discussing whether Iraq was a 20 or 25 year prospect for US forces being there. We expected Afghanistan to be about the same.
Then when I was in Bagram in 2009, I was talking with senior NCO's and Officers there and how the "government" was going and by that point it was a pretty common opinion among the folks on the ground that we would need to keep American ISR and Air Support to back up the Afghans for a solid generation. Not a huge force doing daily combat like early on, but a definite presence to deter folks across the border. [dealing with the Afghan gov corruption was another issue] And yet, supposed Southwest Asia wonks seem surprised here.
Honestly, I am less concerned about the US and NATO citizens still on the ground than I am the Afghani's that were born since 2001. The US citizens had plenty of time to read the writing on the wall. The Afghani girls turning 16 and 17 this year don't even really know what is coming. I'll be surprised if there's less than half a million Afghani's killed in the next year. Not in combat, just straight murdered.