One thing that stood to me was when Joint Chiefs told LBJ to mine the North Vietnam Harbors and attack HO Chi Min trail in Cambodia and Loas in 1966. LBJ said no. Nixon listened to them when he became President and North Vietnam came to the bargaining table.
That makes me think of something a while back I read about that apparently Lady Bird’s business interests and investments (as they were kept all under her name) were tied to government military contracts and thus stood to get rich from the war being dragged out over the years. Not surprising that LBJ basically sat on the whole thing and really did not want to fight to win the war like what could have been done very early on as per your post.
Say what you will about Nixon, he had plenty of guts. Sure, I know he made kissy face with China and gave us the EPA and all, but his mining of the harbors and bombing the north with B-52s is an object lesson in how to wield a sword in a modern war.