The way I see it, you have three choices, the government, corporations, or billionaires. It's an oversimplification of power in this world today, but those are your choices. Which one of those do you pick to clothe and feed and house you, after the singularity happens?

Another potential alternative is healthy capitalism, where a large number healthcare providers are in competition with each other to provide the best service at the lowest cost. In this model a hospital, for example, would be forbidden to buy another hospital down the road, in the same way a doctor’s office would be forbidden to buy a second doctor’s office, because both cases reduce competition.

That would be government. Markets don't regulate themselves and monopoly is the natural equilibrium state of capitalism.

No, it would be a mixed economy, where private individuals and businesses provide most of the goods and services, and the government plays a significant role in regulating the market.

Monopolized markets are almost always evidence of regulatory failure.

"Healthy capitalism" isn’t an option distinct from government intervention. Healthy capitalism it is government-regulated capitalism. Any system where competition is protected depends on active, ongoing government enforcement of the rules. Without that, markets naturally tend toward monopoly or oligopoly.

Advocating for "healthy capitalism," is advocating for a system where government sets boundaries and steps in to preserve competition. That places it firmly within the spectrum of government-regulated options, not outside or apart from them.

It's tempting to imagine ideal or the worst versions of each option and then claim, "what I want is none of these." Instead, we should look at whether our preferred scenario is actually possible within the real-world range of choices. In this case, "healthy capitalism" is only possible when government is both the referee and the enforcer, so it's a version of the government option, not a separate path.

Those are all the same choice

Government. 100%. It has issues certainly as every organization created by humans does, but corporations already run almost everything and that's why most everything is on fire. And billionaires are just the dumbasses in charge of the aforementioned corporations.

Not sure why we would walk into the sea because work doesn't need doing anymore. If you are worried about needing work to put food on the table, I think our best solution is to start with a small UBI that we try to increase as automation increases.

We ? No. I walk in the sea, you go back to work. /s