Why was the Great War so much more protracted than the wars of the 19th century? Why was it so much more deadly? Why do we call it the first total war?

Why was the Great War so much more protracted than the wars of the 19th century? Why was it so much more deadly? Why do we call it the first total war?

Why was the Great War so much more protracted than the wars of the 19th century? Why was it so much more deadly? Why do we call it the first total war? Do you think the USA should have joined the war earlier or not at all?