I can count the number of engines I've seen with 3000 hours on them that have never been rebuilt on the fingers of one hand. And virtually every one of them were in slow speed, long range cruisers with superb maintenance. High performance diesels cause a tremendous drop the average since the go fast diesels often go bang at 600 hours or less. If anyone would like to challenge that, take a tour of the Fort Lauderdale diesel shops and check out the hour meters on some of these boats. You'll find many of them are less than two years old.
Diesel engines are capable of having a long life when the power to displacement ratio is low.
But when they start jacking up the power, beyond what the manufacturer originally intended, that benefit disappears. The result is the maximum amount of horse power you can have and still expect a reasonable service life. At 450, they'll go 10 - 15 years easily. Detroit Diesels rated at 325 hp that hadn't been overhauled since new 1981. Otherwise, you are a victim of the myth.