Classic example of economic profit. They figured out how to do something at a fraction of the cost, and get to print money until the market catches up and prices fall.

Keep in mind that those $3bn are mostly "future" revenues that will be generated over the next 5 years (http://www.spacex.com/launch_manifest.php).

Also that was $800 Million through 2010, we are now 2 years on and counting.