At the risk of continuing the non-conversation here, I feel like it's important to consider countervailing long-term trends. I was listening to a fascinating episode of the Macro Musings podcast with Alex Tabarrok of George Mason and he brought up a very thought provoking point: the largest single group of workers was the Baby Boom generation, the next largest is (broadly speaking) their children, the Millenials. The number of Americans in the workforce is currently at its peak for about the next hundred years simply by number of people in their prime working years. This means that unless automation vastly outstrips the decline in the number of prime age workers, this problem won't directly be nearly as bad as people are saying. This is further reinforced by the demographic trends among the changing generations of workers -- Millenials aren't going into trucking or welding or other not-currently-automated jobs at nearly the rate their parents did.

The obvious followup to that whole point is "what are the comparative effect sizes of all of these various causal phenomena?" I don't happen to have the answer to that, but I feel like it's worth pointing to at least some mitigating factors.