Just as a thought experiment:
I often joke with my friends I wish I were fabulously wealthy so I could pay them salaries to indulge in our shared hobbies, so we could all just do that all day rather than waste our lives in cubicle farms.
Now I'm being silly when I say this, but the statement underlies a basic truth: the entertainment value I'd derive from such an arrangement is worth something to me. Thinking about it carefully, there's many things like that I'm sure people wish were services offered which currently just aren't, because we only have so many people and other functions and goods are far more important.
If I were one of the elites in this automated paradise and I wanted to play World of Warcraft, and it was nothing to me to spend money on such a thing, why not pay people to form a raid party with me? Sure right now that would be stupid, but if there's no other actual use for money because food, transportation, etc. are so cheap they're nearly free, it might make sense.
The point being, since it's human nature to literally want everything, will our expenditures simply not become more frivolous (or perhaps intellectually and emotionally enriching is a more positive way to say it) as the costs of pragmatic needs decline?
I mean we already have people who make their living doing things most people find, well, useless, strange, or stupid (for example people who make a living showing toys or playing video games). Just because the demand for labor for pragmatic things might drop doesn't mean demand for labor in general will, it could just shift to the next most demanded services that currently aren't much of the economy because of the limitations of current resources.
To put this in a more stern way, human nature is greedy and once necessities and many luxuries become ludicrously cheap, people will just demand more luxuries. The demand for labor may simply shift into increasingly less pragmatic areas and not vanish.
Perhaps that's too optimistic, but again it's just a thought. I suspect though some element of this kind of economic phenomenon will come to pass.