That's not my understanding based on Nagl's writings (Learning to Eat Soup with a Knife). My understanding is that the Army decided they weren't good at counter-insurgency, so they avoided it and focused on conventional wars they knew how to fight (i.e., getting ready to fight the Soviets in Germany).
As they say in Congress, “allow me to revise & extend...”. The Army/Marines HAD a lot of counter-insurgency experience coming out of Vietnam — AND they lost it pretty quickly. There didn’t seem to be a whole lot of effort made to retain the body of knowledge gained.