I did Read The Fine Article, and it referenced my first thought, which was "don't the cheap terrorists' drones fly low and slow?". Sure enough, the average third world drone is most likely of the variety limited to 500 feet and maybe full bicycle groundspeed. The F-35 on the other hand...
So is this really a military need? Or just an excuse to spend cash on a new defense system? If ISIS or ISIL or OASIS (didn't they break up after that last album?) or whatever gets drones to fly up to serious altitudes, they're going to be larger Predator-sized clones (clones of drones, as it were) which can be shot down with bullet-sized bullets from the aforementioned F-35 or F-Anything for that matter.
(Sidenote, the 'F-Anything' would be an awesome combat fighter designation.)