Perhaps we've come down to whither doctrine.

Were the historical doctrine examples we've noted, beginning with Gentile's, trailing indicators or leading indicators of battlefield chalenges the respective armies faced?

How does doctrine influence on balance how the force faces its war? Imperial policing and the Boer War had a decisive influence on the British doctrine before WWI. To what extent did that doctrine influence the British response to what the army found in Flanders? By the end of 1915 much of the Old Army was dead.

Countering insurgents for the Army and Marines in Vietnam was countering guerrillas until after 1970. Did the consistent emphasis on find/fix/fight/finish doctrinal solutions address the tactical problems of the ARVN/US Army-Marine Corps? Both guerrillas and beginning in 1965 PAVN units offered lots of fighting but the tactical solution set based on the doctrine couldn't drive operational or strategic actions to defeat the enemy. Experimentation did finally address the "other war" with no small amount of borrowed military manpower.