[Turing_Machine]

Oh not this again. First of all, Friedman advocated a negative income tax as a replacement to the ad-hoc mess of redistributive taxes, grants and welfare programs that exist now.

Yeah, and? He thought it was the best solution to the problem. See above about the difference between political theory and political reality.

Second, this doomsday scenario of 50 million people waking up one day to discover..

Don't give yourself a hernia setting up those straw men. No one said anything about people "waking up one day" to find themselves unemployable. The discussion is quite clearly about a problem that develops in the long term.

[Rumford]

Okay, so the 50 million number emerges gradually. What do you suppose the first million are doing while the other 49 gradually emerge? Unless they're complete derelicts, they're going to be looking for ways to make themselves more productive again. How many of them will not succeed?

There does happen to be historical precedent for this in the many other technological revolutions modern industry has seen. Can you find one that resulted in one seventh of the country just sitting on their hands strictly because they had nothing to contribute (and not because government "safety nets" paid them to do so)?