Fight fire with fire. Anti-drone drones that are near cost parity. Or make some investments to develop, cheap, mobile, relatively short ranged point-defense systems. A middle ground between CWIS and CROWS or a CROWS-like system optimized for drone defense. The engagement distance will be close, but it turns the asymmetry back around.

This is what Ukraine is doing, but it will always be imperfect. Shahed style drones don't fly a straight path. Ukraine has built out an auditory detection network using cheap phones, has mobile response teams for different types of incoming threats, yet it is still not enough.

Given the resources we are using today, while still seeing drones and ballistics get through, does not bode well for a 100% reliable system.