I saw a re-enactment using British military cadets using MILES gear using line abreast tactics against a maxim machine gun, they suffered about 80% casualties by the time they neared the enemy trench line. Using the more evolved bounding advance they suffered 1/3 casualties by the time they reached the other side.
By 1917 the Germans had developed the basics of blitzkrieg by utilizing stormtroopers that would bypass strong points and penetrate as deeply as possible targeting command and control while the "regular infantry" mopped up the strong points.