The Catastrophe, defined as the simultaneous destruction of almost all the Mediterranean cities around 1190 BCE, is taken as the end of the Bronze Age. It appears to have been the result of a military innovation. Widespread collapse of civilization seems sufficient to cause trading networks to lapse.

If trade was falling off before that, it could be that the new iron swords coming out of northern Italy were driving down demand, and metal from the now useless bronze swords entering the market.

Hardly anything written for a few centuries after the Catastrophe survives, so the prospect of resolving the question seems dim.