The debate about whether or not we need HR is actually a genuine debate, so you aren't really making any far fetched argument there, but like I said, that's another argument for another day.
You might be missing my point, you're talking about individual jobs, my point was more broad. What I'm saying is, throughout history jobs have become obsolete, but parallel to that, there have always been new jobs created. For example; HR, there used to be no such thing before the 20th century, now it's a profession, with hundreds of thousands of workers employed all over the world, it's now possible to get a degree in HR, when even 20-25 years ago that didn't exist. A job that has become obsolete, milkmen. What did milkmen do when there job became obsolete, they used their existing skills, or obtained new skills that allowed them to do something else, and that's what lorry drivers will do as well.
The point is, we will always find something to do for work, we always have and always will. There is absolutely no evidence that we are moving towards a world where people don't have to work anymore.