That said, I think you are totally wrong about this. Just look at surnames: Baker, Smith, Shoemaker, etc. The actual names of people and their families were completely centered around their employment, or more generally, what it was they did all day long. Yes, this was medieval Europe, and conditionals abound, but the same is true in many other cultures too. The surnames of Mehta or Poddar in India relate to accountants.
More generally, you mention that people needing to do something for someone else is not what humans should do. I think this is totally false. Maybe not just 1 person/baron/emperor, but I certainly think people want to be useful to other people in their community. Ok, yes, this is a gaussian curve here, like so many other things, but I would like to think that at 1 std south people still want to help others as a natural condition for mankind.
However, I do agree with you and Adam Smith that people should be mostly doing 'nothing' all day. Most of the work to feed and house people in 1st world countries is 'done.' We can easily give out the bare essentials for life, the issue is distribution, as is claimed by Minimum income folks. Though I agree with you in a mechanical sort of way, that is not the issues. The issue is emotions. Giving people free stuff is not 'fair' for most folk. And that emotional issue of fairness, something I think drives a lot of the reasons behind laws and politics, is the elephant in the room. The question quickly come out of 'why should I work if she gets free stuff all the same?' Do not underestimate the ability for people to 'game the system' either for simply the want to appear more well off than their noisy neighbors. Keeping up on the Jones's is why you see so many new iPhones in very poor areas.
Overall, I think people exist on the bell-curve between selflessness and selfishness. Most folk are 1 std north or south of the average. The real questions are where is that mean relative to Jesus and the Devil and how wide is that std relative to that?
Note: Also, time and again we are told that the standard of living here in the US is far too high for the whole planet to be able to live like us. Nearly all scientists worth listening to say that climate change is real and we have to do something about it. Weather we like it or not, the average living condition here in the US must fall to a level our planet can sustain. Possibly we are seeing this in action already.