Well the experts in general are wrong.

Just like one of the few who even predicted this was Kurzweil. Bostrom, Gates, Musk, or many of those with their tiny pictures in the field don't grasp the larger picture. They come to unwise conclusions or understanding often based on emotion.

The data pointing otherwise was published in 2004. The singularity is near, and earlier in 2001 with the law of Accelerating Returns https://www.kurzweilai.net/the-law-of-accelerating-returns

The book is massive and a huge amount of it is data and graph plotting of that data. Kurzweil's theory of how things will go actually matches your first point. We will achieve higher levels of productivity through use of external AI and eventually (likely with BCI's) we will move closer to a synthesis as beings of human/AI intelligence and capabilities. Our productivity in 10 years may be millions of times more productive per person than today for those who do not opt to be left behind like the Amish.

Kurzweil discusses this in his book from a few years ago "How to create a mind."

To take this further with my own theories (my college education and life's study is economics and I've written about the next industrial revolution for years now) Employment will adapt to these productivity levels, the owners will be trillionaires or quadrillionaires, and so long as social status remains tied to wealth, inequality will widen its chasm.

There will be some structural unemployment, there may be a change in tax codes or sentient rights to address AI use, but the world will keep spinning and ultimately those who use AI as an excuse to stop preparing for the future will be left behind in the wake of the singularity.

Ironically I think that these events will practically result in people spending more time at work for several reasons. 1. Longevity escape velocity is predicted to happen 2029-2033 2. Historical evidence, as you pointed out, shows increased productivity doesn't have statistical significance on reducing hours worked. 3. The greater deterministic control of the owners and concentrated wealth results in greater influence over the rest of us.

It's in the wealthy's interest for the rest of us to be productive and busy. Aside from this increasing their quality of life, idle hands might cause mischief. Curing aging along with AGI means there will be little, if any, pressure to increase the human population, and I suspect Post-Humans will derive meaning from their production. In the 2030s I think we will see 68-80 hour average work weeks (not through mandate or force either, but because that's what people will be inclined towards).

The hard question is what happens with each single human+AI becomes 10 billion times as intelligent as the average person today (2035-2040), the exponential gains become increasingly hard to predict from today as we move closer to the technological singularity.