The average suburban American doesn't have fully automatic weapons or RPG's.
The Taliban also at one point did have surface-to-air missiles (specifically MANPADS) but most references to that are old enough that they might have run out by now unless someone's been resupplying them.
I'd take an all-American AR-15 restricted to semi-automatic fire over a rusty old fully-automatic Afghan Kalashnikov.
Not a California-spec AR-15 mind you, but a full bore, Screamin Eagle, Texas-spec AR-15, with a high capacity magazine and all the other bells and whistles.
To be fair, I would fully expect American guerrillas to be able to maintain an insurgency just as effectively as the Afghans, particularly in the Rockies, Appalachians, Alaska, and Cascades. Texas is more flat and wide open, but if you managed to hold the local fuel infrastructure you can do a lot with guys in pickups.
I'd take a squad of dudes with AKs and full auto fire capability over a squad of dudes with ARs. Your tactical options are so much better when you get that extra tool in the toolbox.
The Taliban also at one point did have surface-to-air missiles (specifically MANPADS) but most references to that are old enough that they might have run out by now unless someone's been resupplying them.