> they could have time left for actually contributing to society - anything from caring for the elderly to making art.
That is an assumption that is not obviously true at all. Plenty of people are not creatives and not self-directed enough to do so. But even if they are motivated, can we really be sure that such a soceity would work, because people will know they are not truly needed?
To be honest, already, society seems rather meaningless in some ways and I think a lot of people find meaning in their work that they would not if no one really valued them economically.
And also, people may make art, but automation now also seems to imply that the world will drown in a sea of AI-generated art that may make actually getting such art to a wide audience almost impossible.
To me, it is far from clear than a totally automated society will be any sort of utopia.