Quickly relegated to second line duty? Seems to me they were the
primary shore bombardment force, and the other 'old' battleships that were not at Pearl (The New Mexico class BB's) were sent all the way around from the Atlantic poste-haste, and constituted the only battlegroup defense in the Pacific in the event the Japanese decided to follow-up their air bombardment of Pearl with a more substantial force.... Why would they do that, if the battleships were 'obviously' obsolete (and apparently had JUST been proved so, so dramatically?) As for 'mixed results' for battleship shore bombardment, besides the American efforts, the Japanese battleships and cruisers kept the Marines and Army Air Corps on Guadalcanal in a constant state of alarm, disruption and destruction, with Henderson field under almost nightly bombardment, destroying hundreds of planes, cratering the airfield, blowing up fuel supplies, and killing hundreds of soldiers, Marines and airmen. If it was not for the amazing efforts of the 'Seabees' and the constant flow of replacement aircraft shuttled in by the USS Enterprise and others, Guadalcanal could well have become a terrible defeat for the US! And what finally stopped this carnage? The USS Washington and the USS South Dakota!
Again, I am not saying that battleships are in any way 'better' than either aircraft carriers, or submarines, or any other weapon system for that matter. Battleships had, and still have a role which no other ship can fulfill, and that is to sail directly into 'harm's way,' deliver the goods, and come out the other end regardless of incoming shells, missiles, planes, bombs, torpedoes, whatever. The only thing that can effectively stop a squadron of battleships with its usual escort destroyers, etc, is another squadron of battleships..... They were never designed to operate as single ships, or really in groups less than four, and those that were lost at sea to air or submarine assets, were not being operated as designed, and so therefore these losses were both avoidable and to be expected (if you operate a submarine in war exclusively on the surface, it will be sunk, and very quickly, because it was not being operated as designed, yes? Combat aircraft operated individually by themselves will soon be shot down by aircraft flying in groups, yes? Same for battleships!). In other words, you can use a monkey wrench as a hammer, it just isn't a very good one! I think I have said enough on this subject, and will now leave it to others to continue this discussion...