i suppose there are always exceptions, but the japanese diesel engines used in datsun, toyota, isuzu and others have proven to be nearly indestructible.
i recall working for a time for a roof truss company north of seattle, they gave me an old '81 datsun 3/4 ton with a 4 cyl diesel, they told me maybe i should service it as no one remembered the last time it had an oil change
the oil came out black as sin, but that is no big deal in a diesel, however the thing had 186k miles on the clock and was running the original primary fuel filter, still had the factory marks on it. the air filter i could not get out of the housing, as it was a solid dirt clod
i removed the complete assy, beat it to death with a rubber mallet to get the clod broke up and get the filter out, it to might have been original, i never looked that close. took a steam cleaner to all the piping and housing to clean it out, and put it all back together.
i overheated the thing one morning, the dash lights didn't work, and i had no idea it was hot, broke an oil cooler water hose, and blew the head gasket,... pulled the head, cleaned it all up, put in new gasket and away we go again.
lost the front brg in the trans at 220k, center rivets failed in the clutch soon thereafter, i don't recall why we didn't change the clutch when we replaced the trans.
at 331k miles the little truck was sold for 300 dollars, and for all i know the little bugger is still running somewhere.
it was the only 4 wheel vehicle i could run along side a push start on cold mornings.
a courier company i did business with had 60+ G series 3/4 ton chevy van's with 350 cu/in small blocks, they were impeccably maintained and they routinely got 350-400k miles out of them before they were sold. they had all the normal stuff replaced on a scheduled basis, no running to failure, they knew exactly when to change every part of the van, such as 91k miles for an alternator, 75k miles for a starter, waterpumps, timing chains etc, they hardly ever had a breakdown. and i bought a couple of their old vans for friends to pull the engines out of for other projects.
fwiw, they used series 3, 15/40 motor oil (same as used in the cummins powered fl-70 freightliners) and they changed the oil in those vans every 10k miles!
i never understood how that work, other than the engines started at 5am and didn't shut off again until they came in at around 4:30 in the afternoon. so i have no idea how many hours were on the oil changes at 10k miles but it had to be a bunch.
i think engines can last a very long time with excellent maintenance, and not started, stopped for short runs a dozen times a day. locomotive engines are an example of long lived engine's, i don't think they are ever shut down.
bob g