Why did navies retain old ironclads so late?
Short answerThey kept crews employed and gaining sea experience until modern replacements were available.
NotesFleet expansion depends on trained people as well as new hulls. Paying sailors ashore while waiting for replacements would waste opportunities to build sea experience and make personnel easier to cut. Older ironclads could therefore remain active as employment and training platforms after their front-line combat value had declined. A famous survivor such as SMS Kaiser could also be harder to discard because of its Battle of Lissa reputation. Their continued service does not prove that the navy still considered them modern warships.