Why drone warfare matured after a century

If drones existed in the First World War, why have they become militarily important only much later?

The concept is old, but lightweight computing, communications, miniaturization, and mature command-and-control systems made drones practical at many scales.

First World War experiments, Queen Bee target aircraft, and explosive-laden bomber conversions in the Second World War show that unmanned aircraft are not new. Their modern importance comes from enabling systems such as lightweight computing, satellite communications, data links, and miniaturized electronics. A small camera drone controlled from kilometers away can now provide meaningful reconnaissance at very low cost. Mass and expendability can turn civilian-scale technology into a military problem even when each vehicle carries little payload.