I agree with your point about our choices having some impact but i believe the book of Job's objective was to teach us that although we are spiritual beings, while we are in the physical world, we will not have revealed to us those things in the spiritual realm, nor should we question God and why He makes the decisions he does to spare some and not others. At the end of Job God answers Job's pleas with a monologue to the affect that basically He is the Lord who has created all things, knows all things and endures all things-not Job, not you and not me..so do not question it.. just serve and revere Him. This same theme is found in Ecclesiastes as the author encourages us to live life the best you can, keep the commandments, and revere God because no one on Earth can explain why good things happen to bad people and bad things happen to good people other than to continue to have unshakeable faith in God that it is best.