I'm fine agreeing to disagree that Brees would have been better if he stayed with the Chargers for his entire career to date, and assuming all of the same dysfunction (Spanos organization), coaching staffs (Norv, McCoy, Lynn), and surrounding talent (e.g., mostly poor OL).
But it doesn't even matter. The point was whether or not the Chargers made the right decision at the time on Brees-Rivers. They clearly did, based on contracts, salary cap, Brees's injury at that time, and the talent level of the two players.