In Revelation 18:3 John mentioned that “the merchants…have grown rich.” That obviously implies success in selling. That now no one buys anymore means their source of (further) wealth has dried up. Their lamentation, then, is selfish. Their grief revolves around the fall of Babylon to the extent that Babylon (that is, her inhabitants) can no longer buy and so fill the merchants’ pockets. At bottom, then, these merchants had the same attitude as the prostitute had as described in Revelation 18:7.
11 And the merchants of the earth weep and mourn for her, since no one buys their cargo anymore,