I disagree with this premise, there is still a lot of work to do. We don't even have space elevators, nanobots, immortality drugs and all other manner of technologies yet, and just like every other technological innovation in history, I assume that we will reallocate people to do said work. Work expands to fill the time and space (and workforce) available.
You would have to define work for this to be meaningful. Generally, demand for "work" is unlimited if the price is zero, but demand falls to zero as price increases. Humans are willing to work for at least what buys them "bare necessities", food and maybe shelter (in a madmax-style world.)
In these discussions, it is suspected that AI will "underbid" larger groups of workers than in previous waves of automation.
I've mentioned this before in other AI threads, but humanity has an uncanny ability to use all resources available. As you say, the amount of work will only grow with the increased productivity from AI.
AI threatens to make all human-sourced work redundant. Because AI is really an automated culture machine - in the widest sense. It will eventually be able to innovate, rather than replicate, culturally ground-breaking work in art, science, engineering, business, politics, and media.
What jobs are humans going to do then? All that's left is manual labour - and eventually that will be automated too.
This isn't exaggeration. It's already happening in a very limited way with today's super-crude AI 1.0. AI 5.0 won't be a step change, it will be something entirely new.
But with LLMs we are as close to that as climbing Everest takes us to the Moon. No small feat, but not particularly relevant. After all, all they do is return statistically likely text responses from text inputs, based on a very large corpus of text previously written by humans. Any claim above that is technical hubris and/or funding strategy.