AI creates useless class of humans

Here is a prediction that most people will become useless:

Yuval Noah Harari, author of the international bestseller "Sapiens: A Brief History of Humankind," doesn't have a very optimistic view of the future when it comes to artificial intelligence. He writes about how humans "might end up jobless and aimless, whiling away our days off our nuts and drugs, with VR headsets strapped to our faces," writes The Guardian. "Harari calls it 'the rise of the useless class' and ranks it as one of the most dire threats of the 21st century. As artificial intelligence gets smarter, more humans are pushed out of the job market. No one knows what to study at college, because no one knows what skills learned at 20 will be relevant at 40. Before you know it, billions of people are useless, not through chance but by definition." He likens his predictions, which have been been forecasted by others for at least 200 years, to the boy who cried wolf, saying, "But in the original story of the boy who cried wolf, in the end, the wolf actually comes, and I think that is true this time."

Harari's book is quite good, even tho he does overgeneralize in places and have a leftist bias.

What is going to happen, when the world gets to 10 billion people and the authorities decide that 99% of them are useless?

That is plausible, and if it happens, I think that we will see a mass extermination of the sort that has never happened before. Our grandchildren will wonder why we spent so much effort on non-problems like global warming when we were headed for a demographic apocalypse.