Presumably the weed smoker might occasionally leave home. Someone must pave the road he drives on. Someone must build the weed-smoker’s car.

For all those people doing things for the weed-smoker, someone must manage them. They will work in multiple enterprises. Someone must work to sell things between those different enterprises. This might seem inefficient, but humans have not figured out a better way to do it.

And all that explains exactly why, despite what people prattle on and on about with there being useless jobs, people do in fact remain employed and even as wasteful as that employment sometimes is, there is no better alternative on a social scale. Because when it all comes down to it, people want the benefits that modern society provides. That requires that people work. The alternative is living as a solitary mountain man. Not many people try that—and that, lo and behold, takes even more work.