Why did climbers begin seeking harder routes in the Alps after 1870?

By 1870, the primary motivation for climbers to seek out harder, more challenging routes in the Alps was that all of the principal Alpine summits had already been successfully scaled. With the major peaks conquered, mountaineers turned their attention to finding new and more difficult paths up mountains that had previously been ascended. This shift marked a transition in the sport, moving from the initial objective of reaching a summit to the pursuit of greater technical difficulty on the mountain face itself.1