Hardly. We tried to fight a guerrila war conventionally, and it is the same thing we are doing in Iraq. There were no traditional "lines" in Vietnam the way there were in WWII. The populace did not see us as liberators and we never actually tried to conquer North Vietnam.
We actually adapted quite quickly to the war in VietNam, with tactics like "Search and Destroy," LRRPs Patrols, Ambushes, Mobile Fire Bases, etc.
But on one level, I think you are correct and I take your point: It's my theory that we didn't do enough of this aggressive sort of thing, employing only the merest fraction of the troops we had in country at any one time. But still, despite our hamstrung inefficiency, we still pretty much wiped out the indigenous VietCong, and caused the NVA enormous casualties
Also, please remember that were handicapped by the Johnson Administration. (May each and every member of it rot in a special Hell for it) The war was micro-managed from the White House.... right down to LBJ himself selecting tactical air targets. Thanks to the Walker Family Spy Ring and a giant hole in Naval Communications Security, the Russians read LBJ's foolish instructions before we did and as a result the enemy was rarely surprised.
In the end, we were trumped in VietNam the same way the French were. When they had the Foreign Legion there, the frogs at home were fashionably appalled at their successful operations, and a communist-inspired media campaign forced them to change tactics, and of course eventually pull out after the disaster at Dienbienphu.
Painful. Victory could have been ours.