I think people are underestimating this badly indeed. A lot of people are making comparisons with the coming of the car or the train or the calculator but this is very different as the people who are getting replaced now cannot really move to anything which is not replaced by computers. I think Gates is underestimating it as well; I think lawyers, MDs and a lot of specialists etc are also out. Not all but all the low flyers who are already quite easy replacable and have only some laws to protect them.
Don't like doom scenario's because too many people have them but as a tech guy I don't really see a future without billions unemployed. That does not have to be a problem but we have a long way to go so it kind of depends on what happens first.