I think to many of us in the software world this concept isn't surprising at all. So many products we build, market and support are designed to help increase productivity. Although we might not like to think about it at time, our work helps eliminate the number of employees companies need - either by making jobs redundant now or by helping them slow down the rate at which they hire new employees.
As the cost of labor drops the costs of providing free services will also drop. I can see the world of 2100 having a 95% unemployment rate and zero social unrest. A 10% flat tax could easily support a standard of living well in excess of what we are used to today and the few people that are employed could have access to the new inventions well before the rest of the population.
Put another way, I would rather do most things with 10 million today than 50 million (inflation adjusted) in 1900. You could get more manpower back in 1900, but I would rather have 1 guy using a backed loader than 10 people using shovels.
But why is it desirable to have a society in which the majority don't work?
I don't suppose by 2100 (or even 21000) we'll have done everything that can be done. There will always be something for someone to do. Encouraging people to do something useful with their time is vital to the health of a society, and it's a fact of human nature that that needs both a carrot and a stick.
I think there is a more positive side to this in software than in other forms of automation because software has massively lower capital costs than robotically automating a manufacturing plant. Simplistically, when it requires a large amount of capital to increase productivity, the gains will go to the source of the capital not to employees. GM employees would be hard pressed to start a new car company, and Canfor employees are going to find it tough to start a new mill. But we've seen how software improvements have dropped the costs of running some businesses so low that many more people can run a business than before. If you can't get a job at a company because of software making things efficient, you can probably find a couple of people and compete with them, or do something completely new.
