It's a speedrun to see who can make the cheapest, most effective laser systems. Once you have that, knocking drones out of the sky will be pretty straightforward.
Russia has proved that you can swarm the defences of your adversary using very cheap and very hard to detect drones. I’m on mobile but check for the night attacks the Russians have carried out against Ukrainian towns located on the Danube like Reni, Ismail or Chilia. There’s lots of AA being carried out in those videos but eventually one of those drones always passes through to its target.
So far people have also not really tooled up for that in a cheap way (but the old AA tanks like the Gepard are doing quite well).
Before things went mostly missile based, there were concepts for cheap, automated AA guns (even autonomous) - that stuff might just make a comeback.
But, yes, something will always go through, hence the strategy of destroying production facilities etc. But if defense is cheap and only little comes through the usefulness of drones drops again.
