[trhway]

>would be extremely vulnerable at war with modern weaponry.

the point of those enormous ships is to minimize the chances of war happening.

>More, smaller, near-coast ("littoral") ships would be much more effective tools for wartime

Russia lost the big ship on the Black Sea and have the situation you're describing - ie. their fleet is several missile frigates, and such their situation is very weak. The fleet can't really operate. (And with recent successful attack on a Russian airfield in Crimea the air support for those remaining ships is expected to dwindle which will be a clear show case of how [in]capable fleet without air support (which we do actually know since WWII really), and that air support usually, until you operate near your shores, can only come from aircraft carriers)

[rocqua]

Frigates are much, much bigger than litoral ships.

[trhway]

The US litoral ships are 3500 tons 115m length. Russian Black Sea frigates 4000 tons 125m (https://en.wikipedia.org/wiki/Admiral_Grigorovich-class_frig...) Black Sea is deep everywhere, ie. there is no "litoral" area where those frigates wouldn't be able to operate due to their size. And their roles there are currently mostly those of "litoral" ships, like the land attacks.