So even worse than Saigon then because after 20 years of support there wasn't even any significant Afghani interest in having any other government than the Taliban.
More like a completely disfunctional government made up of a bunch of warlords of dubious background and character. AFAIK the Talibans massacred any possible opposition/contender around the 9/11 events, leaving effectively no cohesive group behind that could replace them.