The functions of the designations change with time. “Destroyer” is actually short for “torpedo boat destroyer” and was a ship designed to protect battleships from nasty little torpedo boats back at the turn of the 20th century, when these things were becoming quite a threat. Then it was realised that they were better at delivering the torpedo attacks themselves than the torpedo boats were, so they took that role on for WW1. Then come WW2 they were pressed into service as sub hunters (largely because there were lots of them) and then they became general purpose escorts, and now (in the RN anyway) anti-aircraft ships.
Guns are still useful. Missiles are more accurate and destructive and have a much longer range, but guns are cheaper and much more versatile. You got to remember that the single Mk45 5” gun on US destroyers today shoots further than the old 5” guns of the Viet Nam era, will certainly be far more accurate, and can probably pump out as many shells as three or four of the older guns. Still I take your point - the worlds navies have largely given up on naval gunfire support. In the era of the guided missile its reckoned to be too dangerous for ships to loiter close to a hostile shore. Ground support is a job for the flyboys now.
Ground support is a job for the flyboys now.
Yep. Most naval assets seem to be dedicated to protecting the carriers. Fortunately the Army and Marines have their own air assets available - and don’t depend on airports. Carriers have to be concerned with their own safety first.