A small UAV force is actually easy to defeat electronically with new developments including jamming communications, and GPS data to prevent the drones from knowing where they are and eventually crashing/returning to base. Kinematic it is also easy to beat with developing radars for short range platforms like Pantsir, Tunguska, etc that are being made especially after Khmeimim airbase incident where Russians figured out they were lacking the ability to accurately track small RCS targets with little to no metal parts. If KSA had had any of these systems they would have been able to thwart the Iranian attack.
The Pantsyr-SM, also known as Pantsir-SM, is an upgraded variant of the Russian Air Force Pantsyr-S ground-based air defense system optimized for engaging unmanned aerial vehicles (UAVs) and operations in the extreme cold Arctic climate. The upgraded air defense system will receive an extensive modernization to intercept UAVs and is expected to be ready for serial production by 2015. The Russian Armed Forces may take delivery of newly produced and older Pantsyr-S retrofitted to the Pantsyr-SM air defense system beginning in late 2015. In November 2017 it was revealed that the new weapon system will use new missiles which will increase the kill range to 40 kilometers.
And then there is laser systems which could have interesting in future because they will never miss really, and can take out targets in quick succession.