We laugh at Russia's "fields of rusting armour" but one interpretation I saw somewhere said these scrap heaps were (plausibly) set up to be a source of components for whatever military requirements appeared next. It also kept the armaments industry ticking along for the last 80 years. The Japanese build two submarines every two years, by two companies. Unless they stuff up, each company can plan developments with forward looking. The contract system in the US has its drawbacks.