Did the 3rd battle of ypres/Passchendaele make the Allies change their battle strategy and help them win?
No. Haig, Foch and co were not ones to change their minds. I would disagree that Passchendaele was the last attrition battle, or that this was the Allied strategy in the first place. From Plan XVII through to the Nivelle Offensive (which effectively crippled the capacity of the French army to launch independent major offensives), as well as the Somme, Passchendaele,Cambrai, Amiens, even the assault on the Hindenburg Line beginning September 1918, all of them were planned and represented by senior Allied commanders as breakthrough battles that would smash through the German lines and swiftly win the war. There was no talk of attrition as a strategy, least of all from the commanders planning and launching the offensives, until well after the war was over. All these battles resulted in heavy Allied casualties; Britain lost more men in 1918 than in other year of the war.
