I’ve worked in an environment where there are no managers for 4 1/2 years and it’s been fantastic. Here’s to getting rid of them in most (but certainly not all!) places.
Now I work at a place with not enough managers to go around, and my team basically has 25% of a PM's time, and no dedicated department head (last guy quit, leadership has not decided whether to rehire). It's absolute chaos. No shit shield between us and leadership, nobody to soak up all the excess meetings required to understand what's going on throughout the company, nobody with political weight to throw around on our behalf, nobody to persist a long term vision for our department. We're working twice as hard to tread water, and creating a lot of technical debt while we only barely stay on top of our basic responsibilities.
It may be that, at an organization that is set up not to have managers, it's better than just being the one group in an organization that doesn't have one. I admit that's a possibility.
But, at another organization, I've actually had great experiences with managers, who cleared the road for me and made me feel like I was doing better work more easily than I was without them. So, on the whole I am pro manager, so long as they are very very very good at it.