To me they're like mere servants of the State, like Lenin talked about in "2. What is to Replace the Smashed State Machine?" in his writing "The State and Revolution"
Under Capitalism, they are its privileged knights that try to deflect and control, if not defend directly its image as "the only option", who have their incentive in doing so, with their class status stake being in their duty to shepherd the means of production and its resulting benefits
However, they don't own the means of production, as they merely manage it for the landholding, industrialist, and financier capitalists
On the other hand, under Socialism, while its privileges will be probably be done away, the PM class on its own would innovated upon, for their new duty of overseeing, managing, and reporting the collectivized cooperatives and state-owned enterprises..
Until the final stage of Communism arrives, I think they're pretty handy
I say this, because I hear such disgusted sentiment in Hexbear against them
You’re talking about project management, (the coordination of people resources and timelines) which is only one of the aspects of management, and is useful for larger projects that you’re only going to build once, like infrastructure or larger experiments.
For these, you would need a coordinator that gathers and prioritizes info, like a planner or project coordinator.
There’s two other components. One of which is workflow optimization, which is for repetitive tasks like manufacturing or information processing. And the other is keeping up employee morale, also known as internal marketing.
For these, a manager is useless for the reasons stated above. However, the workers themselves would need to learn the relevant skills that the managers have.
The work of Taylor wasn't just for projects, but its focus was on measuring activities done in production. You can see those ideas being developed later on with Fordism and further in Toyotism, each with their own breakthroughs.
I think scientific management will develop further in communist societies, since labor need to be organized. One of many contributions of capitalism when compared to feudalism was specialization and then breakdown of very complex processes in smaller simpler tasks. However, in communism, the tendency is that the technical aspects of production will remain while the socio-economic relations will change, since there will not be exploiter and exploitable classes anymore.
Workflow optimization and employee morale will still be important under socialism.
Workflow optimization is just management of people/resources/timelines (and is present in non-repetitive jobs too): what processes aren't working well together, what were the root causes of issues we encountered, how do we fix these problems? This, too, gets better with experience and study and some workers should specialize in this sort of management.
Employee morale (and other aspects of emotional work) will also still be a relevant question under socialism: how do you balance a specific worker's development interests with the needs of the job, how do you manage interpersonal conflict, how do you build consensus for or mediate disagreement raising from decisions the group needs to make? Straight-up boring old motivation questions also do not disappear just because workers have a stake in the fruits of their labour.
And I’m not suggesting that it will disappear, only that it will by done by the team itself, not by a manager who only has a stake in the performance of the team.
If you have a conflict between your DND game and a commitment to your family, you don’t need a manager to help you resolve it. Similarly, if your raid group is optimizing runs for your MMORPG, you don’t hire a manager.
Even if you’re a manager for your team, most of what you do is gather data and feedback from your team and observe their workflow, and then pass that information back to them. That’s inefficiency in movement of information right there.
I think you are very narrowly defining manager as a manager of capital (i.e., seeking to maximize profits without care for what products are being made). I think you should read this: https://redsails.org/the-relationships-between-capitalists/
It is only the last part — the coercive, adversarial role played as representatives of capital — that will become obsolete. The coordination part of management (which includes coaching and motivation and conflict resolution) will remain.
My experience with organizations, from families to RPG groups to community associations to capitalist enterprises, is that in a management void, some people will take on management responsibilities. Since these roles require skill and entail responsibility for certain tasks, it's better to formalize it and train people for it. Do you not also see this in the organizations you are part of? Or could you be underestimating the amount of labour others are putting in to managing your community?