Yet they have basically no air defenses, and the US has stealth bombers with enough canned sunshine to turn the country into a parking lot. So, if raw victory was the concern, it was within the military's power to at any time unleash it.
You are framing everything in a pre WWII perspective. That's your first mistake.
All they had were kalashnikovs, RPGs and indomitable spirit.
All the many variables you may think of renders these expensive toys worthless.
Bottom line is, the US went there to exterminate Talibans, and they lost badly