Commercial fleet and military engines do not 'last' 25 years. They have a consistent maintenance schedule to fix and replace common wear parts. You have to think of it much more like the Ship of Theseus and not the same vehicle.

My last two vehicles lasted over 250k each, well, one is still going, I just don't own it any more. I feel the engine on the Toyota thats still running may last forever. It's replacing other parts outside the drive train that made it not worth it. Consumers are much more into toss and replace than full rebuild maintenance schedules.