Less humans are needed for the production. The world production for cell phones is 1.2 billion is enough for 6 billion humans needing every 5 years a new cell phone.
It was only 15 years ago, I purchased 1993 my first mobile phone. It was no cell phone, they had been with 1100.--EUR to expensive. It was a car set for only 600.-EUR. I had always a 12V lead acid battery for my notebook with me, this was also the supply for the mobil phone. This was at that time only for the rich people in the industrial countries. Only 15 years later reached the production full supply for the whole mankind.
Branch for branch in market saturation
This will happen branch to branch. The production will reach fully supply for mankind. There will be less humans be necessary to work in the production.
Consum conjector 2050
When all happens well, the typical human in 2050 will recharge his 20 year old Plug-in hybrid car with the electric power from his 30 year old photovoltaic. He will never order fuel for his 30 year old plus-energy house.
Following the way of agriculture
In history, the greatest part of the population worked in agriculture to produce food. Today are only a few percent working in agriculture. The production of good will follow the same trend.
Already 1979, it was obvious for some people in the GDR (German people republic), that the system will crash between 1990 and 2000. The system was as unable for reforms, that it was only able to succumb.