Most of the Iowa class battleships took less than four years from launch to commissioning, so in WW2 your last statement would have been challengeable had the USN not realized the folly of building more BBs.
They were all started before WW2. The Montana class was abandoned - maybe it could have seen service if it was continued but it wasn't. In WW2 battle ships were still king of the ocean - airplanes were showing promise but not yet good enough to replace them (though if the war had gone one just a couple more years they would have)
You mean started before the US involvement in WW2.
And the battleship was definitely NOT the king of the ocean. Carriers quickly took over that role, and aircraft quickly made mincemeat of the best battleships ever built, starting with the destruction of Force Z near Singapore and culminating with the destruction of Yamato and Musashi.
