The challenge is to figure out whether or not the most fundamental tenet of economics - that demand is unlimited - holds true.
Even if demands are unlimited, the problem is that automation will drive down the costs of a lot of labor to where regulatory and transaction costs make hiring most people more trouble than it's worth. It's not that there won't be labor people want done, it's that machines will out compete most people in those tasks, making then economically unviable.
Which is exactly what happened for the other 1.4 billion jobs that don't exist anymore in the United States.
What you fear has been feared for a hundred and fifty years, since automation started to seriously replace workers. Instead of driving us to a dystopia, however, it's pushed us into a relative utopia.
What you're proposing isn't new. The implication you aren't addressing is that the trend of -new- jobs, previously not worth employing someone to do, but rising at the margins with increased specialization, arising as workers were freed from old ones will suddenly cease.
As Multiheaded added, "Personal is Political" stuff like gender relations, etc also may belong here.