The only point at which consumers stop demanding is when they die.
People won't die if they won't buy cars, smartphones, luxuries, movies, music, go to fitness, yoga, beauty shops etc!
Which won't happen in socialist communities because they will eat themselves first. Long before technological unemployment is actually a concept, let alone a problem.
Currently there are no truly socialist communities in the world, therefore it cannot happen in principle. But for the most developed countries (which are all free-market capitalist now) technological unemployment is knocking the door. Don't believe?! Look at the U.S. labor participation rate since year 2000.
Look at the example you're typing on. It put a lot of professions out of business. Yet it CREATED hundreds more. Possibly thousands, given the flexibility of the Personal Computer.
We are not going to be outcompeted by robots. We will adapt. We always have, and we always will.
For many people it is just hard to understand what is an exponential growth curve (technology advancements follows it). No doubt new jobs will appear, but after some point their number will be less than jobs automated.