Past technological breakthroughs: The combine harvester. The cotton gin. The water-powered loom. Factory robots. Clothes-washing technology in general.

Proposed technological breakthroughs: Self-driving trucks and cars. Warehouse robots. Supermarket robots. Automated drones.

Every efficiency advance not matched by an equal increase in demand reduces the need for people to have jobs.

Self-driving cars, travel websites, self-checkout lines, Amazon's automated shipping centers, the first fast-food restaurant that lets you order with a touchscreen instead of having your order taken incorrectly by a minimum-wage drone, possibly Watson as a replacement for low-level customer service/tech support

I believe some fast food places have introduced apps through which you can send your drive through order in advance.

The drive through window with its crappy speaker and on-the-clock ordering experience is currently pretty poor.

1 drone replacing 50 soldiers on the ground?

Imagine the efficiency increase if countries just did Starcraft 2 match instead.