In Product Cost, I was taught that the cost of an article consisted of Material, labour and overheads. So if anyone was not actually producing, they were an overhead. BUT, you do need folk to sell and service your product, so some level of overheads, other than utilities is needed for the enterprise to be viable.
But, my view is that a lot of jobs would be unneeded, if we weren't so lazy, unskilled, or disabled.
For over forty years I maintained my, and others cars. Now they are much too complicated for me to do that, (Lack of skill and facilities on my part! ) Plus, lying on cold concrete is no longer as thrilling as it used to be!
Electronics are now WAY beyond me, so another lack of skill / facilities.
Some, but not by any means all, evils are a necessity, it seems.
Howard