I'm not sure why the thread is about Austin. Congress waived the requirement for his lengthy of time for separation from the military. He was confirmed with 93 yeas. I have no idea if he's a good sec of defense, nor does anyone else on the board. Whatever he would like to have done concerning the withdrawl, it's clear Biden limited troop levels, and that limited what the US had the capacity to do. Same goes for Miley.
At some point, the Taliban will let everyone go, or not. We'll see. the 200 figure seems to be about right, according to the NYT, but I'm not sure who knows, really. The Taliban need intl support to govern, and Afghan seems unlikely to feed itself.
Biden didn't foresee the Afghan Army folding so fast. Neither did the Taliban. Biden doesn't appear to have issued any warning to people to get out by a certain date, and he owns that.