Looks like you are keeping up with maintenance. These Cummins run forever. The rest of the truck always wears out first. How does the rest of the truck look.
That engine is not even 1/2 worn out. They are also designed to be rebuilt. Usually good for 400,000 miles before the 1st rebuild. However the rest of the truck will be far worn out. The seat, steering, suspension, body and frame, etc.