‘And the word of Yahweh came to me saying, “Son of man, what is this proverb that you have in the land of Israel, saying, ‘Time goes by, and every vision dies'.
The proverb is literally, ‘The days, they lengthen and every vision, it dies.' The point being made is that time goes by but none of the prophecies come to fulfilment. Thus when the people hear a prophecy they shrug their shoulders and say, ‘it has never happened, it will not happen now.' Proverbs can be very valuable, but they can become stilted and meaningless, resulting in apathy.
These people were aware of the prophecies of past prophets, of warnings about the coming ‘day of Yahweh', and they considered that nothing had happened. How easy it is not to see in present history the fulfilment of God's warnings. They were here in captivity, having witnessed Nebuchadnezzar's successful campaign against Judah and Jerusalem, but had not see in it a ‘day of Yahweh', for Jerusalem still stood.