As long as human want is never satisfied, there will always be a job to do. And if that isn't right, in however many decades you are worried about, consider how much you complain while enjoying leisure, how you wish you were working - you probably don't. The point of using machines is to Decrease our labor and Increase production, making less work for ourselves. The more productive we can be while doing less work, our standard of living increases. We are made better off by increases in production, which makes goods better and cheaper, and not by work itself. So if we run out of work to do, we can all rejoice, stay home on steemit, or do other activities we find more valuable. But that won't happen.
People have been worried about this for generations but turn out to be wrong every time. Here is likely your response, already said by someone else:
"That may have been very well in the past, but today conditions are fundamentally different, and now we simply cannot afford any more labor-saving machines." - Eleanor Roosevelt 1945
Don't be this wrong. Embrace the freedom of movement and choice that are afforded to us by using machines in production.
RE: Doug Casey and I Destroying Commies On Universal Income