Global trade was far more limited prior to the establishment of US hegemony. During the age of empires, merchant vessels often had to carry weapons for protection and/or travel in escorted convoys. All of that leads to higher costs, delays, and the complete closure of indefensible routes.

No one is seriously claiming that global trade will disappear. But from a historical perspective the current frictionless system that most people take for granted is an aberration and we should expect some reversion towards the mean. Whether that's a good thing or not is a matter of perspective.