Why interim large-calibre naval guns are a poor investment

Would it be worthwhile to bring back conventional six- to twelve-inch naval guns until new technology arrives?

Probably not. Long shipbuilding timelines mean an interim gun system could be obsolete or retired halfway through its intended service life.

A temporary return to six- to twelve-inch naval guns is judged unlikely to be worthwhile. Shipbuilding takes long enough that the new technology could be ready by the time the interim ships entered service. The result could be paying off those ships halfway through their intended lives to build replacements. The objection is to the timing and expense of the stopgap.