With enough artillery and men it actually did work in many cases. The large scale assaults regularly made progress measured in miles. The problem was that you c

With enough artillery and men it actually did work in many cases. The large scale assaults regularly made progress measured in miles. The problem was that you couldn't meaningfully continue an advance or exploit a breakthrough. Once you left your trenches you also left your supply lines. The enemy could respond to any breakthrough with overwhelming force mobilized by their own rails and roads.