[hogFeast]

The working day was 10-16 hours for most of the 19th century. But work then was totally different: a lot of it was piece-rate work, most factories didn't directly employ anyone, etc. (this was also true of proto-industry which is often used as some kind of proof that working conditions can be different).

This came down to 8 hours per day as the labour movement grew stronger. The concept of burnout makes no sense outside of the present, it was just politics. The move to 8 hour days was faster in countries that had tighter labour supply and/or greater political representation for working people (i.e. Australia and the US).

The structure of work has rarely been determined by efficiency. There is a greater context of norms, other obligations that people have, economics, politics, etc. Even within the developed world and within individual countries, there is significant variation. Indeed, the only limits within most countries is at the extreme i.e. an employer requiring 12 hours of labour without a break or something.

The most "efficient" kind of work is piece rate. Some people do this today but I think that most people chose not to do this because it is inconvenient.