I have anticipated the mass use in combat of drone swarms. While commercially available drones will quickly be rendered useless in the battlefield, electronic modification kits will quickly become available to retrofit them. Vulnerabilities to major militaries include the logistics train of fuel trucks and supply trucks that must follow the main army. Those are not going to be protected by drone defenses at the same level as the front line troops, but without them the front line troops can’t fight. What good are your Abrams tanks when they can’t get fuel? A devastating attack against an air base far from the front lines can be carried out by a man on motor scooter wearing a backpack with a drone in it.
It’s going to take a small company to develop and deploy effective solutions as the large military suppliers I worked for scoffed at small money and small projects. If it wasn’t big enough to be listed on the main corporate assets sheet, they weren’t concerned with it. Also, big companies, are, by design, very slow. The longer a project lasts, the more money they make. Drone projects are the sort that need to be turned around in near real time.
As the US Army advanced in Europe in WW2 it investigates all manner of things, including what had knocked out German tanks. One surprising finding was that only a single digit percentage of the Panzers claimed as knocked out by “tank buster” rocket firing allied aircraft could be found. Prisoner interrogations confirmed that Panzer crews had been very concerned about rocket firing aircraft, but also that these prisoners admitted that few of them had actually seen a tank taken out by rockets.
That surprised the Army brass, because they had observed that Panzer units repeatedly attacked by tank busters on their way to the front were greatly weakened and generally performed poorly. Upon further review, the Army concluded that even though the tank busters kill claims were wildly exaggerated, they were nonetheless responsible for devastating Panzer units caught moving up to the front.
The rockets might not seriously damage a Panzer without a direct hit at an unlikely place and/or angle, but they were orders of magnitude more effective against the thin skinned support vehicles in the column. So even if the Panzers of a Panzer unit made it to the front, their stocks of fuel, lubricants, ammo and spare parts did not. Neither did the logistical and repair personnel. They were dead, wounded, or, if they survived the destruction of the irreplaceable support vehicles, being pressed into ersatz infantry units.