The least expensive way to make low sulfer diesel (and therefore the way it is done) is to strip the sulfer out with a hydrogen treatment. This also strips out some beneficial lubricity, so older diesels have excessive injector and valve wear. Newer engines are being designed for low sulfer fuel. (Older gas engines suffered valve seat recession with lead free gas and they designed new valve seats for that.) Caterpillar is pretty much the largest diesel engine manufacturer in the world. I can't imagine them getting out of making diesel engines, not even just over the road or US engines.
Growing old is unavoidable. Growing up is optional.