They knew that this world and all its riches are nothing more that a velvet-lined Cartier box. Angels of G-d ascending and descending on it. He is obliged to involve himself in a material existence. Our actions in this world directly influence the way the spiritual realm interacts with the creation. Even the angels depend on the ladder that man creates by his actions in this world.
Man is the dominant force and the focus of the entire creation.
You corrupted yourself, Israel, for your help is only through Me. A great king once asked one of the sages of Israel why it was that, at the time of the destruction of the Beis Hamikdash, so many thousands of Jews were slain. The sage replied that the Jewish People had always put their trust in Hashem saving them, and He had always protected them. They had never concerned themselves with the strategies of war, rather they had always poured out their hearts in prayer and offerings. Therefore, when the Jewish People sinned, and consequently lost Hashem's protection, they were left bereft of any defense at all.