“And you said, ‘I will be a lady for ever,
So that you did not lay these things to your heart,
Nor did you remember its latter end.' ”
But Babylon was supremely arrogant (compare chapter 14). She abrogated the role of the everlasting God. No one could be sure of the future for ever except God. But she was so sure of her own everlastingness that she did not consider her behaviour or her doings, nor consider that all earthly things have an end, and that that end would be determined by her behaviour. She believed that she would last for ever and retain all her privileges. She did not need God.
To be a lady meant to be pampered and cosseted, and because of Babylon's glory, and her reputation, that was what happened to her. She tended to be treated as special even by conquerors. Esarhaddon of Assyria restored her. Assyrian princes ruled over her. Cyrus the Persian made her a capital city. She was clearly used to such treatment. Thus because she was used to being pampered she assumed that the gods, even Yahweh, would pamper her. That is why she did not consider her ways. She was presumptious. Nor would she bring to mind what the consequences of such evil behaviour would be. (Even though history had revealed it often enough). She thought she was eternal.