These are all very cogent arguments, with much going for them, and I have heard them all before. HOWEVER..... Before we write off the whole subject, allow me to make a few last points...
Most of the arguments about manning, training of crews, etc. are essentially a 'chicken or egg' scenario. If the ships (any ships, for that matter!) were in continuous service, then there would be a continuous supply of such people (and this is why so few other navies have fleet carriers). Same goes for powerplants, armor production, etc, as the 'gear up' time required to produce any large and complicated piece of machinery is quite extensive, quite expensive, and only pays off through time and volume. In other words, if battleships had CONTINUED to be produced, or at least remained in commission, then the ships we MIGHT have had currently would not only be far more economical, but far more capable as well, and fully staffed with experienced personnel (but I fully agree, the surviving battleships really are relicts at this point). How expensive and troublesome do you suppose it would be if we decided for some reason to mothball all our fighter planes for 20 years, and then decided to reactivate the air-fleet? Where are the pilots? Where are the mechanics? Where are the spare parts? This is going to cost a LOT! See what I mean?
But the REAL point I would like to make involves the CONCEPT of the battleship, and frankly, I don't think that concept ever became less viable, but was just PERCEIVED to be. Over and over again you see it written about how battleships had become 'obsolete' even before WW2. The disasters at Taranto and Pearl Harbor certainly indicated that under the right circumstances, they were in fact not the invulnerable juggernauts they had been considered to be prior to this time. BUT, a closer look reveals that in fact battleships had ALWAYS been vulnerable to SOMETHING (submarines, torpedo boats, mines, etc, and each time it was considered the 'end' of the battleship!), just as EVERY weapon system has its weak points. However, I suggest that the battle experience of the battleships in WW2 reveals less about their mission capability and viablity, and more about the STRATEGIC and TACTICAL abilities of its proponents. Namely, battleships were NEVER designed or intended to be 'single ship all-powerful entities,' but to be used in squadrons and fleets, but almost NEVER were during all of WW2.
To explain further, consider the German Reichsmarine. In WW2, the Germans never had more than two battleships and two battlecruisers. Hardly sufficient when confronting the Royal Navy, let alone the US Navy as well. Yet they STILL managed to confront some significant elements of the Royal Navy, caused some casualties (Hood, POW, etc), and had opportunities for even more mischief, even if they didn't quite work out as planned. Considering the odds they faced, it is surprising they ever put out to sea at all, and certainly there was never an opportunity to operated as designed, as a squadron. At the same time, just by their EXISTENCE, large parts of the Royal Navy were tied down as necessary counters, just in case the German ships broke out again. And the ships designated for such oversight duties were not just carriers and their planes, but other battleships, cruiser, destroyers and submarines, and thus represented a significant portion of allied 'combat capability' devoted to just one purpose; to keep those few ships bottled up, and/or destroy them where they lay. With this firmly in mind, is it any wonder, at least in regards to the German vs British Navy that 'battleship vs battleship' confrontations were few?
As regards the Japanese, this is more of a mystery, and appears to be more a fault of employment, rather than capability. After examining the Pacific campaigns for many years now, it appears that 'battleship vs battleship' confrontations didn't happen often primarily because the Japanese simply didn't commit their battleships, but kept them in home waters at anchor for most of the war. In fact, with the exception of some coastal bombardment at Guadalcanal, and a couple night actions using no more than a couple essentially unsupported battlecruisers, the Japanese didn't use their battleships for much of anything until Leyte Gulf, and by that time, they had so little control of the air that the whole affair was desperately pointless, regardless of what ships they could or could'nt have mustered.
In other words, the battleships of WW2 were NEVER used in their intended role, i.e., in a squadron, pushing forward to confront an enemy squadron to achieve control of a piece of ocean, not that opportunities to do so failed to present themselves. So you see, it is hard to say they were 'obsolete' if they were not used as intended.... This is not because they couldn't, or that such action would not have been effective, but because they CHOSE not to! There were MULTIPLE surface ship gun battles in the Guadalcanal arena, mostly involving cruisers and destroyers, only two of which involved battleships, and only one of which involved a single Japanese battlecruiser, vs TWO US battleships. What if the Washington and South Dakota had not encountered just the Kirishima and a couple heavy cruisers, but a COLUMN with the Nagato, Mutsu, Ise and Hyuga, let alone Yamato? I don't think we would be having this discussion if such HAD happened!
Further, it is interesting to note that even when EVERYTHING was stacked against any possible success by the Japanese fleet regardless of the operation, in their last great effort at Leyte, the Japanese battleship Yamashiro managed to drive against all odds, through aircraft, MTB's, ranks of destroyers and cruisers, ONLY to be finally destroyed by the assembled gun line of Oldendorf's 'old' US battleships, sailing as a squadron in 'line ahead' and 'crossing the T,' exactly as they were intended when first laid down. One can only wonder what the outcome might have been if it had not been ONE Japanese battleship, but a half-dozen operating together as as squadron, not separated by miles of ocean, dying one by one as unsupported individual ships.....
Finally, as far as the concept of the current employment of a battleship, I submit to you that it is not necessary for a battleship to lie 10 miles offshore to do bombardment duty. A battleship can get as close to shore as the sea-bottom allows. Certainly many places are shoal, which would preclude such a close approach (and monitors were designed with this in mind), but you could certainly approach with a mile or two in MOST places. And mines are for minesweepers. Yes, the battleship would attract fire, and that is the point. On one hand, it would be able to ABSORB such punishment, but more importantly, would be able to counterpunch such attacks (counterbattery fire) very effectively, and with pinpoint accuracy once they revealed their locations by firing at the battleship. Oh, and one more thing, a 16" shell does not cost several million dollars, as does a single Tomahawk, and it can be sent downrange on request literally in a matter of seconds, and God help whatever it hits! And yes, a standard 16" shell can hit targets 27 miles away, but RAP (rocket assisted shells) more than double, or even three times that distance, and really, if you need to hit a target THAT far away from the seacoast, you should be calling on air support, not a ship!
The lastest craze is for the 'Littoral Combat Support Ship,' which is that peculiar stealth thing you see pictures of on occasion. While I am sure it can dodge lots of Radar, and unleash a lot of missiles, I wonder how many shells and missiles it can absorb? Yes, armor piercing warheads are dangerous to armor, and they have been around a long time, both for bombs, shells and missiles, and I am not saying a battleship, or any weapon system is invulverable to them, just that it takes a LOT of them to stop a battleship (HOW many bombs and torpedoes was Yamato hit by before she sank???).