Exactly. Those machines/processes/knowledge are a form of capital, and failure to redistribute it through taxes has known consequences in inequality, poverty, etc.

Not arguing that inequality is not an issue, it certainly is. But to say that only the wealthy have benefited distorts the picture. Rockefeller or Getty could have spent all their billions and never owned an iPhone, or had a child in vitro, or videoconference with a person in another continent, things taken for granted by everyday non-billionaires.

The average person's "wealth" -- as measured by life expectancy, access to vaccines, medicines, and advanced procedures, clean food, safe shelter, labor laws (in most countries) plus an enormous variety of entertainment and leisure options -- continues to increase over time, even if wealthy people get the majority of the gains.

Yes, increasing efficiencies of production have mostly benefited owners and a relatively small slice of high skill workers. (Like the engineers who build systems to remove human labor from processes.) Displaced workers in high income economies have seen their prosperity diminish because they lose a lot of earning power without seeing it fully counterbalanced by lower prices. In fact, inflation targeting efforts (and a host of other factors) keep inflating the costs of health care, housing, and higher education in an era where improved techniques "should" be making everything cost less.

Quoting from the article, Elon Musk has apparently said "There will certainly be a lot of job disruption because what’s going to happen is robots will be able to do everything better than us." I don't think that the story is "more of the same for ordinary people, and even worse" if machines can take all routine, productive jobs [1]. If owners don't need ordinary people as employees, then neither do ordinary people need owners. If machines do everything, then the cost (and price) of goods and services falls toward the costs of raw materials and energy. And raw materials and energy themselves fall precipitously in cost if machines can perfectly build more nuclear reactors or solar farms and batteries and mine even low-grade ore deposits without wages or breaks.

In this scenario, ordinary people don't even need to seize the existing assets of rich people to start living well without them. Just have the robots make copies of everything. There are a few edge cases of positional goods where robots can't duplicate things (you can't make more Old Master paintings or Manhattan real estate), but those don't really stand in the way of broad prosperity. If robots do everything routine, then everyone can have good medical care, clean water, plenty to eat, safe and climate controlled housing, abundant electronic entertainment... pretty much everything that the median adult citizen of highly developed countries currently enjoy today.

Keep in mind that I'm not saying that machines will replace human workers in all routine, productive jobs. I'm just thinking about the effects if they can.

[1] Routine, productive jobs would include things like driving trucks, diagnosing and treating leukemia, picking apples, and running experiments as planned by a principal investigator. It wouldn't include things like writing new poetry or coming up with a novel line of research as a principal investigator. But nonetheless, the "routine" jobs include most of today's economic activity, including most that are currently high pay and considered high skill.