Texture at the rear is a little messed up.

Terran is correct on this, I would further stress that the Montanas were ditched because of Carriers period. Flat tops were prioritized capitol ships between 1940 and 1945. US shipyards built some 151 (completed) and about a couple dozen more under construction by the end of 45.
We got 2 North Carolinas by the time Pearl was destroyed 4 Dakotas shortly after, and soon after that 4 Iowas for fast fleet escort, A role the battleships inherited from cruisers to force relevance. The Montanas didn't stand a chance.

Montanas weren't replacing the Iowas, they were supposed to work together. Iowas were the fast part of the fleet and the Montanas the heavy firepower. Basically battlecruisers and battleships from WWI fleet tactics. When aircraft carriers emerged as the future of naval power the Montanas were ditched because their 28 knot speed couldn't keep pace with the carriers while the Iowas 33 knot speed kept pace to let them defend carriers even at flank speed.

should look up the Montana Class BB that were about to replace the Iowa's

That's a very slick looking mash up. Hypothetical Vietnam era refit? (60's)