I've been fortunate to know good lawyers that have made my life easier, reduced the stress of dealing with hard situations. I've seen investors take chances on long shots that succeed, and wouldn't have had any hope without that investor help. I've had excellent managers (and some not so good) that championed my professional development and growth and took care of details that made it easier for me to focus on my core work. You're pointing at the worst parts of things and using those extremes to say they're not necessary. I see this view a lot on HN: Engineer == Good because they produce easily tangible output, and those with less tangible output == Bad.
These professions with less tangible output aren't zero sum. They're the necessary infrastructure of massive organizations, large projects, civilization itself. Calling them zero sum is sort of like saying pipes are zero sum because they just take water from one place and put it in another. It's a bit more complex than that.
Society has to have rules. Society is big, there are lots of domains. There need to be experts that understand those rules and help lay-folk navigate them. That's lawyers. Some are awful, do bad things, make things worse, we produce more of them than necessary, but civilization doesn't really work without them.
Similarly, the economy is huge. Allocation of capital requires people to oversee that process. There's your investors. Many are awful and greedy, but it's a necessary process unless/until we find more efficient ways of allocating capital-- And while programming itself is not capital intensive from the equipment perspective, it is from the "human capital" perspective. The burn rates of many startups will show just how intensive. Again, investors are "plumbing". They're positive sum because the entire system, which is positive sum, requires them to function.
Large projects have lots of moving pieces. At some scales, it's near impossible for a single person to have it all in their head, much less focus on a full time programming job while they're at it. All the moving pieces require coordination. Integration into the non-programming parts of a company require coordination. Managers do this. Plenty are mediocre at it. Others play power games. Some make things worse. But overall the system wouldn't function without them.