Hi SchleptikWhen it says that Jesus thought it not robbery to be equal to God, it is telling you that he did not set himself up like Satan did against God.
I agree that when one reads verses like Philippians 2:6 they must always relate it to the fundamental principle on which the Bible was written. Genesis 3:-5 gives the reason for the Bibles existence.
Genesis 3:3-5 3 but from the fruit of the tree which is in the middle of the garden, God has said,You shall not eat from it or touch it, or you will die. 4 The serpent said to the woman,You surely will not die! 5 For God knows that in the day you eat from it your eyes will be opened, and you will be like God, knowing good and evil.
Jesus made it clear by constantly giving credit to his Father and by demonstrating that he had not come to Earth to attempt to seek equality to God like Adam had done, but to demonstrate that a perfect man, could when given free choice, and tempted like Adam, would not grasp an opportunity to try to be like God that was the primary reason for the Bible been written.
Had Adam not sinned there would have been no reason for writing the Bible because Satan would have been incorrect in his challenge to Gods authority there would have been no need to have a perfect man show that when tempted with free choice refuse to seek equality with God.
To destroy Satan and Adam, and not allow a future perfect man be subject to the same test, would have left the issue of free choice unresolved.
All the Best