How did you arrive at that conclusion? Dividing infinity by 1m or 1b doesn't matter if it's really infinite. Just make more machines to make the machines. The existential crisis happens afterwards, and people will kill themselves off without the need for any class warfare at all. In fact the owner class will die first since there will be no more conception of ownership, since everything is supposedly abundant and at your fingertips.

You really believe today's billionaire class will just give up their power over the populace? A world of abundance means the billionaires are irrelevant because everyone would have access to everything and they would never let that happen.

They will hoard the resources, land, anything that is needed for people to stay alive.