The changing reality is that not everyone can be employed. It has already begun to a minor degree but can only accelerate from here.
Agree. Our society now tolerates lifelong unemployment from people who are not physically unable to work. We just let them carry on cranking out kids on social assistance. It's not a great life, but they have a roof over their head, food, basic levels of idiotic entertainment.
Automation will reduce labor needs. To some degree automation allows the same person to do more, and thus the business need not lay people off. If they can make more they can sell more. However, in other cases there isn't really a need for more supply. The market is saturated, and so automation simply decreases head-count. Think about a mcdonalds for instance. If it can automate most of its local food production, it still can't increase sales (even if it were much cheaper it still cannot infinitely increase demand), and so head count goes down.
Robots are increasingly cheap and able to replace workers. Think about automated cashiers. They suck now and we all know it. Now, picture an automated cashier that involves you simply putting all your food onto the conveyor belt and a camera takes a picture and competently identifies what to get and estimates its weight, etc. Now everything is done immediately and you need only a bagger; no longer a cashier.
People get smarter at a rate slower than machines do.