The US has been playing with these kinds of lasers for over a decade now. Last I saw a demonstration, the laser wasn’t powerful enough to just zap something. It had to focus on a warhead and heat it up until it exploded. It wouldn’t work on a missile in flight. Maybe they improved it, but I suspect the introduction of slow drones like the Iranian Shahed made it feasible.

The cost per shot was pennies a decade ago. But how fast can they shoot these? It must be able to shoot fast and constantly if you want to deal with swarms.