It is true that autonomous drones are a new thing. But 90% of the reporting I see on "drones" is about small radio-controlled aircraft, which have been around since well before the computer.
Is it just that the possibility of a "smart" drone is drawing attention to the other kind, as well? Or is there something specifically about quadcopters that captures the public imagination?
Quadcopters, on the other hand, can be purchased for $40 and flown by somebody with no experience. Obviously a $40 quadcopter won't be threatening airliners, but it's representative of a big change all over the spectrum.
(also, due credit to laptop hard drive 'freefall sensors' as another contributor).
Combine that with the cheap lithium battery and digital radio communication chipsets, also driven by phone volumes, and that's why 'radio controlled helicopters' are no longer a niche hobby, and instead a danger to aviation.