The Russian navy is a bunch of rusting hulks crewed by glorified conscripts. People have been trying these tactics in the mideast against the US for decades, and they haven’t worked since the Cole.
As for interceptors, they are meant for ballistic or cruise missiles, which are also expensive. Ask the Houthis how effective they are. CIWS or RAM/ESSM should be able to handle drones easily, it’s just that commanders don’t want to take the risk.