Also, drones are currently being flown by soldiers in fpv goggles so swarm is not very practical. It will change once we have swarm software and there is a need for it.
There's also nothing that practically stops those same tactics from being aimed at other soft infrastructure targets: electrical substations, telco facilities, water treatment facilities... the nightmare scenario is taking down transmission lines and switching stations outside, say, a large nuclear power plant during a heat wave. The nuke itself is hardened, obviously, but who cares if it can't transmit the power it's generating to the people that need it?