Agreed....I keep reading replies stating the 404 or 416 Rigby can provide the same attributes as the 375 H&H. This is simply not true. They are both wonderful rounds no doubt! But neither provide the versatility of the KING. Wouldn't you feel a bit silly using a rifle that fires 350-450 grain bullets, with a very healthy dose of recoil, at an Impala at 400 yards? The 375 is not the best rifle for this application either, but it's a huge step in the right direction.
I think if we factor in rifle size and weight, bullet selection, ammo availability, and recoil, we could never put the 404 or 416 in the same class as the 375, when it comes to versatility.