I'm just not as ready as some posters in this thread appear to be to declare all "repetitive, mindless" work to be something we should all be attempting to avoid at all costs.
I think the term "at all costs" gives a misleading impression of the views of those disagreeing with you. My view, and I think of many other folks who are advocating for the UBI is that a lot of kinds of work are on their way towards being automated
unless there are dramatic government or societal interventions to force those tasks to continue to be done by humans.
So far from "at all costs" a lot of work is going to go away at zero cost to you the taxpayer/consumer/individual. Now dealing with the potential negative societal consequences of that work going away, yes that does have costs, but so would any attempt to prevent the work from going away in the first place.
In some cases, I think it makes sense for our government to purposefully subsidize some workers' salaries to make it more cost effective for companies to employ humans, rather than mechanizing everything. While it may be true that if a company had to pay its workers, say $15/hr, the company would be better off buying a machine that only cost $50/hr to purchase and operate but replaced 5 workers who would cost the company $75/hr. One option is we could just pay the displaced workers a UBI and allow them to stay home, but a better and cheaper option, I think, would be to subsidize the workers' wages at $5/hr, so that the company could afford to continue employing its 5 workers, instead of replacing them with automation.
I'm not sure that I agree with you that this option is better and cheaper, but it is quite helpful to know that part of your motivation is trying to get the same ultimate effect (not having millions of displaced and hungry people who cannot afford to feed themselves and all of the negative social consequences thereof) but at a lower cost.
I agree that in your example above, paying the company $5/hour to continue to employ humans is cheaper than paying the workers not to work directly. The problem is that the example assumes perfect information: we know exactly what the machine costs to purchase and operate, and exactly what the workers cost to employ.
However, in this real world that $5/hour subsidy would be a moving target as prevailing wages in different sectors of the economy and different parts of the nation changed,* and technology continued to improve year after year. If we tried to set fixed subsidies across the whole country or large economic sectors large proportions of the subsidy payments would be "wasted" (paid to support jobs it would not have been economically viable to automate yet anyway, while lots of other jobs might still vanish because even if the subsidy it was cheaper to automate them. If, instead, we tried to adjust the subsidy on a per job basis, companies would have little incentive not to lean on their numbers to make automation look cheaper than it really is and make workers more expensive than they really are in order to extract subsidies that were much larger than were actually needed to make workers competitive with automation. Tracking and projecting all of this information, as well as policing it for fraud, would become extraordinarily expensive while probably still making a lot of mistakes.
So while I agree that is seems like it should be cheaper, I fear that in practice it would either be less effective than the UBI at ensuring social stability by making sure people aren't worried about being able to feed themselves and their children, or end up costing significantly more than just cutting everyone a check.
*Plus turnover rates (recruiting and training a new employee is much more expensive than continuing to pay an existing one), fringe benefits (changes in the cost of healthcare), questions about how you apportion the cost of maintaining supervisors, payroll, and HR departments among all the individual jobs those positions support, increased or decreased exposure to legal liability (if John and Sally in social media marketing are replaced by a bot, the company doesn't have to worry about being on the hook when John sues saying Sally created a hostile work environment and made unwelcome advances at the office), etc, etc.
Again, I think there's a fundamental difference between people who are posting on this board, most of whom are planning to or are already FIRE, and people who lack adequate skills to be competitive in the 21st Century marketplace and are, therefore, forced out of their jobs, or can't find jobs to begin with, because they don't have anything to sell that the market values. I have a feeling that handing some people in that second group a monthly UBI check for doing nothing may end up having unintended negative consequences.
I have to fundamentally disagree with you on this part of your post for two reasons.
First of all, you assume the groups are non-overlapping. People tend to be under estimate how easy it would be for their own job to be automated, but have an easier time seeing how the other jobs could be automated. My favorite statistic on this: "90% of responders thought that up to half of jobs would be lost to automation within five years. ... But, paradoxically, we found that everyone thought it was going to happen to someone else. In our survey, 91% don’t think there’s any risk to their job."* I certainly think my own profession could shrink by half or more in the next 5-10 years. Hopefully I'll be FIRE long before that, but I realize many other people in the same situation as me won't have that option. So anyway, my point here is that I don't think it is realistic to say that those displaced by coming rounds of automation are "fundamentally different" from you and me, because they very well could end up
being the two of us.
Secondly, about those unintended negative consequences. I tend to think we humans are more alike than we are different. So in the absence of specific data to the contrary, I tend to be wary of predictions of the form "oh yes, of course you and I would do (right choice), but in the same situation those other people who are different from us would do (wrong choice) instead." In the experiments which have been tried with a UBI, we saw many positive consequences, some of them unexpected, and few negative ones. Now, I will be the first to admit the existing relatively small and individually only ran for limited number of years. But, while they may not be conclusive, right now they're the best data we have.
*Source:
https://qz.com/1153517/ninety-percent-of-people-think-ai-will-take-away-the-jobs-of-other-people/