Diesel engines last longer ONLY if you mean the block and even then there are numerous people having to have very expensive repairs ($5,000 to $8,000) on Duramax engines with injector repairs, head gasket repairs, Ford 6.0 with multiple engine parts failing) with fewer than 100k miles on the engine. Diesel powered trucks still have battery and electrical problems and cooling system problems and transmission problems and emission control system failures, and these are all very expensive to repair.
I can have a V8 gas engine completely rebuilt for what a new set of injectors costs for a diesel engine. No way are diesels cheaper to operate for pickup truck owners. Diesels produce more torque for faster acceleration and the engine braking is great but it comes at with a big price and it would be naive to think otherwise.
Part of the price of having a diesel powered truck is that I have to include in my route planning where I will be able to find a station selling diesel. Most small towns only have gas available at the pumps.