The first thing that popped into my head was manufacturing, but production can include a lot of things
It also includes primary industries - such as mining, farming and forestry. These, too, have in many ways been transformed by automation.
For example:
- As far back as 2013, the mining industry began using driverless haul trucks, and this is now quite commonplace.
- Go into any commercial forest these days, and you will hardly see a person in sight whilst logging operations are taking place. A single hydraulic excavator fitted with a harvester head has six times the output of a chainsaw equipped eight-man bush crew.
- Farmers, too, hardly need to employ anybody anymore. Even milking cows has become a highly mechanised process, with most dairy farms now utilising such plant as rotary cowsheds. (These enable an astonishing number of cows to be milked in a 24-hour period; very important in this part of the world, where farmers do not receive a single cent in the way of subsidies).
If everybody just worked their own land without kings or rulers, there'd be no need for taxes or tariffs.
The trouble with that idea is that it only takes one bad season, and you would have famine. This was very much the case during 16th Century Europe. On average in those times, one summer out of three was a poor one, the harvest failed, and people then starved.
The same thing still happens today, in those places where people still rely on subsistence farming. (Sorry - but I myself have observed this firsthand). Then, if famine relief measures do reach the people so affected, it is often provided by governments of developed countries.