Its unlikely that Harpoons, with a 500 lb warhead, could have sunk a WWII capital ship. Many of these vessels took much worse hits from multiple equivalent weapons, many of which were even heavier armor-piercing shells, and underwater hits from torpedoes also.
Even destroyers are known to have survived multiple hits from equivalent weapons, such as kamikazes loaded with 500lb bombs or the like.
Granted the Harpoon warhead is higher tech than WWII weapons of similar weight, but it can’t be that much better.
“Its unlikely that Harpoons, with a 500 lb warhead, could have sunk a WWII capital ship.”
The Harpoon can blow the antennas off of any WWII ship and take it out of the fight.
It could be sunk later by any available platform.
IIRC, Harpoons use a much more powerful (weight for weight) explosive compound (DESTEX) than anything non-nuclear in WW2. It also delivers all of it and doesn’t have to crack a heavy shell to get out. WW2 battleship armor piercing shells were something like 2000-3000lbs and had less than 100lbs of bursting charge. Most of the weight of the shell was the actual shell itself, not the explosive.
Yes, it really can be a lot better.