Regular NVA divisions backed by tanks, artillery and MiG's overran Saigon, not Vietcong insurgents, who were wiped out during the Tet Offensive back in 1968.
Yes, you're right. And I know that many RVN units performed admirably during those terrible final days. But IMHO, the analogy still holds. Afghanistan will end up exactly like Vietnam did.
Well, not exactly. After taking South Vietnam, the North did not then use it as a base to attack the US. After taking Afghanistan, radical islam WILL use it as a base to attack the US (again).