You lose the most with depreciation on a higher priced model. Figure 10% a year for the first 5 years and half of the price of a truck selling for $65,000 will show more of a loss or cost of ownership than a truck that sold new for $35,000.
A different aspect of this with regard to truck are the regular cab work trucks as they tend to take a beating with the type of use they are put to for the most part.
The less I pay for a truck from the dealer the less I will lose from depreciation. My last diesel cost me under $43,000 and others paid over $55,000 for the same truck and guess which owner will be most out of pocket at the time these trucks are sold.
If someone is concerned about depreciation it is usually a good idea to buy a truck coming off a 2-year or 3-year lease as the first owner took the biggest hit.