The answer as to why the USN doesn't have a ton of smaller PT-boat/speedboat style craft is that they're easier to damage or sink than a big Arleigh-Burke. And as we have seen since the end of Persian Gulf War, if a Westoid country doesn't instantly win a war with a flawless victory the narrative is that it lost. The Pentagon doesn't want headlines about American casualties from small patrol boats getting ACKed. It's stupid in a pure military sense, but political considerations have always fucked with pure military considerations. It's worse now than it ever has been though. That's where the West is as a society (that we live in)