And, did you confirm it wasn't your 12-13yr-old timing belt?
BTW...I contacted and had a conversation with the long-time QC guy for Isuzu [on this issue]. Posted what he said about a year ago.
You also missed the part about additives -- that can be used as early as mile #1. And, personally, I do believe there's people who will neglect maintenance in the first 30k. For example, I'd bet big money that MORE people ignore the requirement to change diff/trans fluids at 30k [than doing this procedure]. I'd bet there's a good chunck who start forgetting the oil changes too...and don't check the oil.
Unless you bought a car new, and performed every single maintenance task yourself, you have no idea what happened to your truck.