I've thought about this as well. Various factors contributed to ultimately displace the trade routes from land to water. These factors range from Mongol invasio

I've thought about this as well. Various factors contributed to ultimately displace the trade routes from land to water. These factors range from Mongol invasions, to geography. When trade stopped the flow of ideas stopped. The current geopolitical conflict is about preventing the shifting of trade routes back to land from Western controlled waterways. It is amazing to me to consider for example Armenia's history and see the constant back and forth between a west and east aligned contenders and see its echo it contemporary events. Ditto for the overall high level connectivity between east and west, and how its shifts mirror civilization balance between East and West.