I once saw the invoice for a "routine mobile service" whereby the friendly mechanics from Mercedes Benz show up at your door to perform an oil change and basic inspection.  If I recall, the invoice for not even two hours of work was $800, paid for by wireless Point-of-Sale machine.   A Honda might only take 5L of oil, but a 5-6L V8 motor with a large sump might take 12L of oil at $20+/Litre of factory-labelled synthetic oil.  Including the filter, you might be looking at $300 just for the parts!

The biggest reason for delaying oil changes that are unnecessary, are simply environmental.  Think of all the oil that our vehicles use for lubrication.  If we are all changing the oil at a proper interval, think of the huge quantity of oil that wouldn't be required.  

Do you throw out your shoes and tires with 50% tread remaining "just to be on the safe side?"  Why is oil any different?