This is the problem with a lot of economic reasoning. The 'rational actor' construct works in toy models, but is much less useful in reality.
I took a couple years off a long time ago. I didn't stop working on stuff. Really, if you pay me, all that means is that I work on what you want me to work on, and maybe show up at particular times. It doesn't motivate me to work, it just motivates me to change topics.
I absolutely know people who would never work again. I know other people like me, who do it because they enjoy it. And details matter a lot, and tend to be ignored[1] by simplistic first-principle reasoning.
A big part of this is the ratio of those, and how quickly the number of jobs drop. I would fully expect this sort of thing to need tuning as it goes - I personally see the biggest change being a sudden explosion of people with lots of free time. Just as a tiny example, what does this do to the video game market? What about dry cleaners when fewer people wear business-drag?
Anyone who makes confident predictions based on econ101-style reasoning is simply dressing their politics up in an argument from authority.
[1] What does assortive mating look like under such a scheme - how much status will holding a job gain? Is the income set at an "uncomfortable" level, how will that change over time, what sort of barriers (class, academic, opportunities, etc.) will grow up around it? Are there any incentives to do something useful, even if it isn't what we think of as a 'job'?
Details really matter.