The sailors are not asking for a literal answer to their question so much as expressing their horror at the extent of their loss. For with “Babylon” destroyed, the destination for the goods they are carrying is gone and thus they have lost their source of income. More, since their livelihood is rooted in an earth-centred mindset, the destruction of “Babylon” is irreplaceable as long as their focus remains on this earth.
18 and cried out as they saw the smoke of her burning, “What city was like the great city?”