To me there's no other way to look at this other than having faith in our ability to find work to do. Wherever there is deficiency in technology, humans will find a way to fill in. Now the question is whether this will be at the same scale, and will there always be gaps to fill in. No one knows. We never have known. We've just blindly innovated and had faith. It's worked so far. Until it doesn't we will probably just continue doing it.
In other words, this is and has always been unplannable. An example. When DARPA invented the internet, no one explicitly said "We're going to put a bunch of mail staff, brick and mortar commerce employees, etc, out of work so we better ensure we train programmers to help fill the void."
I'm with you though; it concerns me.