Fibre optical drones have their own challenges. Can't easily loiter or backtrack due to issues with snagging, and their range is more limited.

Autonomous drones, likewise, have their own issues. Mostly they can't be equally dirt cheap, as they need to have all the electronics that make regular weaponry expensive.

I think we are 1-3 years away from a capable autonomous drone with some AI capabilities built-in that can take matters into its own hands.