In a well oiled org managers aren't needed. I know it because I've been part of one. It needs specialised skilled workers i.e., product owner, product designer,

In a well oiled org managers aren't needed. I know it because I've been part of one. It needs specialised skilled workers i.e., product owner, product designer, project manager, and engineers. There'll be a tech lead among engineers who will be point person for the project manager. That's it. At the top you need execs or business heads liaising with product owners and/or project managers. Managers however become essential when this well oiled machine is thrown off by a sudden expansion of the team or when there's a chronic uncertainty about the work that's going to happen next month. Then you need whose who are good at navigating this chaos through networking, politics etc., to get the work done as well as making sure the team survives should the axe fall.