This isn't really an argument for making people do useless work. If we'd just pay them the same amount but without making them do the work, it would be an overall improvement. It wouldn't be game-theoretically stable, though, and as we know, game theory is the strongest force in the universe.
I'm going to be the last person to defend capitalism as a way of organizing labor, but I think that a capitalist system where every company is actively producing something valuable is preferable to the capitalist system we have today.
Of course it sucks to occasionally lose your job, but in a system that's more efficient at allocating resources, this shouldn't be as big of a problem as it is today. I would expect purchasing power to be greater across the board and we would have a more prosperous standard of living as a baseline, primarily because labor isn't locked up and wasted in organizations that don't actually produce anything of value.
Usually people that are comfortable losing their job are lucky to live in world regions where finding a new one is easy, regardless of their age, or population demographics.
What kind of argument is that? I don't think there are any world regions where goods and services appear out of thin air, so how exactly does a society that operates in this way survive and prosper? Do you think every bullshit, non-producing job should be kept around indefinitely to avoid a temporary discomfort of finding a new job?
Eventually for every person working the fields, manufacturing goods, and delivering them to you, there will be 5 people "working" a bullshit corporate job that doesn't create any value. Then the system will crumble under its own weight even with "100% employment" because nobody is actually producing anything. This is just the worst ideas from communism combined with the worst parts of capitalism.
Writing this might make me sound like a hardened capitalist who doesn't support labor but that couldn't be further from the truth. People who lose their jobs should be taken care of - but crucially it should be done fairly, through unemployment benefits or UBI or whatever idea makes sense. That ensures that everyone has access to the same benefits, not just the few lucky ones who land the right bullshit job at the right bullshit company.
