I'm not sure I understand why people are saying a diesel truck has higher operating costs? it certain has much higher purchase cost (more on that).. but the far better fuel economy more than offsets the higher cost of fuel. The oil changes are less frequent when you have 3 gallons of oil in the sump. 15k mile oil changes vs 5k mile oil changes.
The lifespan of the engine with a 350k mile life expectancy is where you offset the initial purchase cost..
So where's the extra operating costs?