It was never going to end any other way. Honestly, this isn't even Biden's fault. It was a forever war, or this happening. No matter when it happened, it was going to. The Neoconservative fantasy is responsible for this.
Yes and no. There's a little nuance here.
If we had opted for a punitive campaign, a la Desert Storm, we'd have been over and done with long ago. But because (as you correctly note) the neocons get a big stiffy for 'nation building' and 'forever wars', well... we were still there after 20 years.
By comparison, the Allied occupation of Japan after World War 2 lasted seven years.
Now, Trump rolls into office, upsetting rice bowls left and right. He looks at Afghanistan and says, 'OK, enough is enough. Time to bring our boys home.' He makes a diplomatic overture to the Taliban, secures an exit date of May 1st, 2021, and informs the Afghani government that it's time they put their big boy pants on and stop fucking around.
Unfortunately, the PTB don't LIKE that, and Trump 'loses' the election. Biden rolls in, and because the derp state/proggy narrative is to NEVER EVER let Trump have a point in the win column, Biden's handlers opt to alter the deal. Except they're not Darth fuckin' Vader.
And to no one's surprise, the Taliban gets pissed off. And when May 2 rolls around, they go on the warpath and start rolling up Afghan territory through military conflict or just subverting local commanders via bribery. Suddenly they're at the fucking gates of Kabul.
We should have had sufficient airlift to move everyone -- Americans, Afghanis allied with us, and equipment -- staged and ready. But we didn't. Because we were using it to ferry fucking illegal immigrants around the U.S.! What a BRILLIANT plan!
So it's a mad dash for the exit, abandoning a shit ton of military hardware and more than a few civilian Americans in Kabul. Way to fucking go.
But hey, no more mean tweets, right?