How is this a point? We have replaced agriculture jobs with tons of other jobs, we have a 5.5% unemployment rate. We have a higher population and better quality of life. Your points do not do anything to suggest we are heading for uncontrollable unemployment.

Are you just arguing to argue? I answer this exact point 2 paragraphs later. This point of mentioning agriculture is to point out that automation can replace jobs without new jobs taking up that slack in that sector. This proves that there is no underlying property of the economy that will create new jobs from the replaced old jobs. The new jobs had to come from an entirely different sector.

Yes because despite your claims to the contrary, nobody can actually see the future. The inability to tell you specific future jobs does not mean those jobs will not exist. Not a single person in the 19th century would have been able to tell you about any of the jobs that exist today, yet these jobs still exist.

In the 19th century we knew about manufacturing and the service sector even though they weren't as big a percentage of the economy as they are now. As automation eliminated jobs, new jobs were created in already existing sectors. What new sector is there after services? The trend of automation is coming very quickly. For you to be right we'd have to discover an entire new sector of the economy and grow it fast enough to support mass employment. That has never happened in the history of mankind.

So for example maybe jobs in space might take off. How many people can that possibly employ in the next few decades?

Manufacturing didn't always exist. Services didn't always exist. Your claims that the economy must be composed of 3 main sectors is a non-starter.

As I pointed out above they certainly did exist at the point where agricultural jobs were in decline due to automation.

Automation only works within the economy, the economy only works with employment. The economy is a feedback loop that is ever changing, it is so immensely chaotic that to do this day we still cannot accurately model it.

Ahh.. The whole it will work out somehow approach again.