Wow. Your misunderstanding of this war is astounding.
Comparisons with Vietnam and Afghanistan v. Soviets are major stretches. Vietnam was receiving financial support and supplies from both China and the Soviet Union. The Afghans were basically armed by the United States. Does the insurgency have consistent, well-organized support from a major military superpower? No. That's why improvised car-bombs and kidnappings are their favored forms of combat...it's all they've got. Can we restrict them to the point where they run out of funding, run out of supplies, andn run out of morale? Probably, but it will take time, probably years.
Second of all, popular support is behind democracy. The vast majority of the country, while not necessarily pro-US, is against the insurgency.
Third of all, only one part of the country is hotly contested at this point. The South is more or less stable. The Kurdish North is stable. It's all about the Sunni triangle, and there's no reason what the US is doing in Fallujah can't be repeated in other smaller insurgent bases.