Avodah Zarah 54 - Why God Did Not Destroy Idols
If idol worshippers abandoned their idol, and it occurred in a time of peace, the idol is permitted, for leaving the idol on their own free will is a sure sign that they nullified it. If, however, they abandoned it in a time of war, it is still prohibited, since they may have left it as a result of confusion.
Philosophers asked the Jewish Sages in Rome, "If God is not favorably disposed toward an idol, why does He not simply get rid of it?" The Sages answers, "If people worshipped something that the world does not need, God would indeed get rid if it. But behold, they worship the sun, the moon, the stars - should God destroy the world because of fools?"
The philosophers then said, "If so, let Him destroy every idolatrous object that is not necessary for the world." The Sages answered, "Then an argument could be made that we are encouraging the worshippers of the sun, moon, etc., for these worshippers will say that theirs' are the true deities, for they were not destroyed while other forms of idolatry have."
Art: Winslow Homer - Moonlight