From what I can tell, they did serve on both oceans

Yes but first and foremost theoretical backing of every capital ship the USN built from about 1900 on was with an eye towards being used against Japan. Institutionally for 40 years there was no enemy the Navy expected, trained, or shaped themselves to fight more than the IJN.

Not totally relevant but important to note.

Another consideration is that the NC and SD classes were built and designed under the Treaties still, and in both cases the USN chose to go with heavier firepower over a potentially faster ship, including the 16in guns on both, over a ship that could truly keep up with as fast as the carriers could go.

The other large consideration is when there would have been time? As the 6 ships were completed there was immediate need for the slipways they had occupied both for the Iowas, repair of the Pearl Harbor and other damaged ships, and Essex class carriers.

And of the 6 when they did need repairs they were rarely sent stateside where such an extensive change would have had to occur for more time than was absolutely needed, North Carolina was repaired at Pearl after taking a torp, Washington did have to go to Puget after the collision with Indiana but was there a total of about 2 months to get her repaired as quickly as possible not make the structural adjustments required for a new bulbous bow.

South Dakota spent a total of about 6 weeks in yard just repairing the damage for 2nd Guadalcanal again mostly just fixing what was actually broken and adding more AAA as she was needed back ASAP and resources limited. Indiana was repaired at Pearl after to collision and her late war refit was still mostly in receiving upgrades/AAA and fixing what was actually broken. Massachusetts during the war only put in for an overhaul once, and like the rest mostly got new radars, new AAA and attention for her main battery (barrels relined). Alabama, despite only being commissioned in August 1942 still got a trip to Puget in early 1945 but it was mostly to better serve as an AAA barge.

So in the end it most be concluded that it was a combination of being designed under strict limitations, coming on line just before or after the outbreak if war creating great need, then ship yard space and resources being very limited. Especially when the ships were able to contribute meaningfully as is.

Then with the ships being placed in reserve the Navy was experiencing HUGE budget cuts in the late 40's and it would have been insane to dedicate the time and resources to ships which they were unsure when they would need again or be able to return to active duty if ever, when there were more pressing needs for the funds.

Good book on them being U.S. Battleships: An Illustrated Design History by Norman Friedman, lost my copy in a move last year and picking up another as a Christmas gift to myself.