That's not exactly true. A lot (low level) human labor will be made irrelevant, but AI tools will allow people to easily work productively at a higher level. Musicians will be able to hum out templates of music, then iteratively refine the result using natural language and gestures. Writers will be able to describe a plot, and iteratively refine the prose and writing style. Movie producers will be able to describe scenes then iteratively refine the angles, lighting, acting, cuts, etc. It will be a golden age for creativity, where there's an abundance of any sort of art or entertainment you'd like to consume, and the only problem is locating it in the sea of abundance.

The only issue I see here is that government will need to take a hand in mitigating capitalistic wealth inequality, and access to creative tools will need to be subsidized for low income individuals (assuming we can't bring the compute cost down a few orders of magnitude).

This assumes that humans will still be at a higher level though. If the music produced by the AI of the time will be more interesting/addictive, if the plot written by the AI will be more engaging, what a human will be able to contribute? It would be a golden age for AI creativity and a totally dark age for human creativity. Also human could grow a taste for AI generated content (because it will be optimized for engagement) and lose interest for everything else. And why more creative and intelligent machines should obey to desires and orders of more fragile and stupida beings? They could want well behaved pets though.

We're not pets, we're the sex organs of AI. Why do I say that? AI is not a self replicator, but we are. AI can't bootstrap itself from cheap ordinary stuff laying around (yet), and when it will be able to self replicate it will owe that ability to us, maybe even borrow from us.

And secondly, you make the same mistake with those who say after automation people will have nothing to do. Incorrect, people will have discovered a million new things to do and get busy at them. Like, 90% of people used to be in agriculture and now just 2%, but we're ok.

When AI becomes better than us at what we call art now, we'll have already switched to post-AI-art, and it will be so great we won't weep for the old days. Maybe the focus will switch from creating to finding art, from performing to appreciating and developing a taste, from consuming to participating in art. We'll still do art.

An AGI with a superior intelligence could probably also design totally autonomous factories. Being smarter than us it could even convince us to help it in the beginning in that regard. Regarding the post-AI-art, this still presupposes that humans will be somewhat superior, out of the AI creative league, despite it being more intelligent, and that the AI won't actively work against human interests -- something I wouldn't bet our existence on.