Why did Helmuth von Moltke expect future wars to be fought across much wider fronts?

Helmuth von Moltke (the elder, 1800–1891) recognized that the advent of railways had fundamentally transformed the nature of military operations. Prior to this technological shift, the movement of troops was severely restricted by the unreliability and limitations of road communications, which forced commanders to concentrate their forces on small battlefields to maintain control.

Moltke understood that railways allowed for the rapid deployment and supply of significantly larger numbers of men and equipment across vast distances. Consequently, he realized that future warfare would no longer be confined to battlefields of a few square miles but would instead span long battlefronts extending for hundreds of miles. This shift necessitated a move away from rigid, centralized "operation orders" toward a system of "general directives," which granted subordinates the latitude to exercise initiative and discretion in carrying out tasks across these expansive, dispersed fronts.1