The implications of the lethal, portable drones for ground combat have not yet been worked out, David Hambling notes (in Swarm Troopers):
Soldiers can see the enemy at a distance and attack them with incredible precision. If someone is shooting at you with machine guns or rockets, you can hide behind a wall or in a hole. There is no way of taking cover from LMAMS short of being inside a closed bunker. It can fly around to attack from any direction and can dive into trenches. This makes it unique, and the tried and tested tactics of previous decades will have to be revised. Lying flat and keeping your head down may simply make you an easier target.
In the future, firefights with rifles may become as rare as stabbing with bayonets. The real action may take place at longer ranges without any face-to-face contact at all.
[…]
You have to fire a lot of unguided weapons to score a hit. For rifles and machine-guns, a figure of twenty thousand rounds or more is often quoted for every casualty. Artillery and mortars fire hundreds of rounds, tearing up vast areas of landscape without hitting a target. Guided weapons are different. From their first use in the 1960s, laser-guided weapons were hitting the target more than half the time. With such weapons, range is irrelevant: a target is as easy to hit from two miles away as from two hundred yards. A squad with twenty LMAMS is likely to score close to twenty hits — which may be on vehicles, firing positions, or individuals.
Not mentioned: the importance of equally cheap reconnaissance drones (longer range, better visuals and loitering time).