Yes, it can be that a person isnot given riches because they would destroy themselves with it. God by His providence does work this way some times.
Just because a person has desires to be a pastor, doesn't mean that God put that desire into them. Many have had a desire to be a pastor, and many have brought the Name of God such shame and disgrace. A true man of God doesn't care about riches anyway. Paul said that by God's providence, he learned to be content in all things.
I do not believe that Job lost his wealth, children, and cattle, etc, because he could not handle them. I do however believe that God wanted to show Job that He does whatever He pleases, He is no man's debtor, and that all good things come from Him.
We must remember that covetousness is a sin. God knows the intentions of the heart, and tries the reigns. He does not let us be tempted more than we can bear; however, He may let satan tempt us so that we can see what is really in our own hearts. As Samuel Rutherford once said, "the devil is a master-fencer to teach us how to handle our weapons."
One man's medicine is another's poison. Let us always focus on our own walk with God first and foremost.
Hope that helps a bit.