It always involves some amount of suffering. Entire generations of people have found themselves in a life dedicated to an obsolete skill. Does that mean we should limit the use of, say, printing machines so that people may be gainfully employed manually copying books?

What you're suggesting seems to be to limit innovation for the sake of comfort. A society that buys such a line of thought is far more doomed than the one who may or may not innovate themselves obsolete.

Hey, I am not suggesting there's a solution-- let alone even suggesting that we preserve jobs by "limiting innovation" (if that could even be done). All I am trying say is that there had better be something hard thinking about what will happen to people whose jobs become obsolete in large numbers. If recent history is any indication, it seems that we're NOT headed towards increasing the size of the welfare state. Instead we're seeing larger and large rifts between the haves and the have-nots. That's a serious problem and not one that has an easy solution.