I used to think that, but it just means you haven't worked with a good manager. Which isn't surprising since they are rare. But they exist.
A good manager will keep all roadblocks and distractions out of your way so you can be in the zone most of the time and they will play the corporate politics on your behalf so you get interesting projects and promotions.
A most dramatic demonstration of this happened at one company where I had my best manager ever succeeded by my worst manager ever. The worst wasn't a bad person or anything, just incompetent as a manager.
Under the great manager I was convinced this was the best-run company ever. Never any emergencies, never unreasonable requests, could focus all my time on interesting projects in different parts of the company. It was so great.
Then the great manager left for greener pastures and the incompetent one was hired. None of the upper management changed so the company was running the same as before. Suddenly I was inundated with nonsense escalations every day, constantly being pushed to stop working on the interesting projects, unreasonable time demands, etc. None of this was orignating from the incompetent manager directly, it came from the SVPs above.
So turns out the awesome manager was just absorbing all this noise and keeping those in his team shielded away from it so we could happily focus on tech work. The incompetent manager just forwarded everything that came to him.
Less than 6 months after the manager switch, I also left the company.
Middle managers are a totally different beast altogether and are supposed to be coordinating resources for strategic rather than tactical goals. It's a lot easier to coast in this position, however, as many competent frontline managers often have the same skill set.
If engineers build things with no business value, then that company will fail. When every engineer is building their own passion project, then the company fail.
The position is a leadership role, one that should ideally ensure the team is united on one goal and is able to exert pressure outside the team in defense of that goal. However with any leadership role, the best people for that role aren't always the people who seek the role.
But also sounds like you've never worked for good managers. They may not do actual work (but many do!), but they definitely know about the technology. They ensure blockers are removed, questions are answered, obstacles are overcome, and that motivation remains high.
They may or may not be rarer that bad managers, but they do exist!