> Falklands war shows otherwise.

Well, actually, the Argentinians had no trouble delivering high explosives to UK vessels, but they did have a great deal of trouble getting those explosives to sink those vessels ... mostly because their bomb fuzes were incorrectly set or inappropriate for the delivery profile.

But on a more serious note, none of the ships sunk by air attack in the Falklands were large military vessels. The largest vessel sunk was the Atlantic Conveyor, and that was (1) a civilian cargo ship built to civilian levels of durability, and (2) it was carrying a large quantity of ammunition essentially unprotected (unlike how a large warship would carry it). Even then, the missile strike and fire did not sink the ship immediately. For the largest military vessels sunk by air attack, the two Type 42s Sheffield and Coventry were relatively small destroyers (less than half the displacement of either their USN contemporaries the Spruance/Kidd or a modern Arleigh Burke) and again there the Exocet strike and resulting fire did not sink Sheffield immediately either. The smaller Type 21 frigates lost, Antelope and Ardent, were never really meant to survive meaningful damage and yet both remained afloat overnight before sinking. For comparison, the roughly contemporary USN frigates, the Perry-class (larger in displacement than the Type 42s), survived both Exocet (Stark) and mine (Samuel B. Roberts) strikes.

(The General Belgrano was a larger military vessel lost to submarine attack with, but considering that it was a treaty-limited 44-year-old light cruiser operating unprepared for submarine attack, it is hard to draw too many conclusions about modern ship durability from its loss - and her sisters in the Brooklyn class generally survived quite a punishment in WWII.)