You can do what you want, but all of the engine manufacturers call for oil changes at least annually, and with good reason. Today's oils are as much additives as oil and the additives have a shelf life. It's your money and you can take the risk of contaminants and ineffective additives. I would expect that a lot more people subscribe to following the manufacturers' recommendations than your theory. And if you are within warranty or have an extended warranty, your extended changes would void the warranty on engine repairs.