Why should only one person out of every five do the honest work of producing what all of society needs or wants, while the other four get to live off of the work of that one? Whatever “great things” you think that 80% could accomplish, you know that no matter what support system might be put in place, if they don't have to work to support themselves, they won't. You'll just have a large population of lazy, unproductive parasites, supported by a small population of honest workers.
If the point is truly reached where society can maintain the same level of productivity and wealth creation with only 20% of the labor now needed, would it not make much more sense to have everyone work much shorter hours? One could work only one eight-hour day a week in order to earn the same standard of living that one now must work forty hours a week—five eight-hour days—to earn; or better yet, work somewhat longer hours than that, say, twenty hours a week, and enjoy a much higher standard of living than is available to most people today?
The political wrong has long tended to support “equality” in the sense of all people being able to enjoy an “equal” standard of living; but, as this thread demonstrates, not equality in the sense of everyone having to contribute equally to earn that standard of living.
In fact, this thread has painted an almost caricaturish picture of the wrong-wing fantasy in which a guy who sits around all day at home smoking dope and doing nothing whatsoever to contribute anything to society gets to enjoy the same standard of living as someone who puts in forty hours of hard work each week at an honest job.