Yeah, we don't know where measure/countermeasure is going with drones, yet. The article mentions body armor, but as you note there are other possibilities.
Jammers have some inherent limitations - they're completely ineffective against wire guidance, which is already in use, and wire guidance could be enhanced with towed kites and laser comms (the kites provide altitude for direct line of sight at long range).
I think hard kill air defense has more potential 1/2
@graydon @cstross
We already have a time tested weapon good at taking out small highly maneuverable flying things - the shotgun. Currently, infantry are equipped with assault rifles, but replacing the assault rifle with a powerful shotgun might make sense.
An automated sound/visual drone detection/tracking network could tell the infantry where to aim, and the shotgun does the rest. Ammo is cheap compared to the drones.
2/2