We will not benefit from fewer people working..

Well you won't have any coworkers who are just there for the paycheck and actually have zero interest in solving the company's problem.

People don't need to be motivated by high-minded ideals to make useful contributions.

Of course they don't - and that's fine. All throughout our evolution we would of had children and elders who would have had limited productivity. Now with automation, how many less people do we actually require to work? It will be very few - it will definitely be more people than the minimum required.

The upcoming AI/robot automation apocalypse means that we are going to have fewer people working. The question is how we're going to deal with that.

That article covers what happens before the apocalypse. What happens after it, i.e. after the point where AI and robots can not only do our current jobs better than we can, but also all of the ones we could possibly retrain to?

Unless AI and robots become effectively humans, they will not be able to do our jobs better than we can. And they do become effectively humans, we will have much bigger things to worry about than unemployment.

Elon realizes this, hence his warnings about AI - how we deal with it is build a better bot that counteracts EvilBot 1.0.

How do you know?