I said in the Modern Management books that managers lead and serve the team (at all levels). However, I've seen organizations try to separate the leading work from the serving work. That's when the organization creates “people” managers. The people managers serve the team by creating a trusting relationship with each person on the team. The other senior experts are supposed to lead the technical efforts and coach the people on their technical skills.
The people managers are supposed to serve the team, but they can't lead the team.
Why? Too often, these people managers don't have sufficient functional expertise to coach every single person on a cross-functional team. They might have expertise in two of these areas, but not all: development, testing, product management, support, deployment. How can these people managers support all those people?
Since these “people” managers don't understand the details of what the various team members do, the organization still needs senior experts. Those experts still coach people in test, development, product management. (Do you still need experts if you have communities of practice? In my experience, yes.)
Does the organization need to separate leadership from serving the people? No. Instead, the managers can collaborate.
Consider Management Collaboration First
If you have a typical product development organization, as in the image above, your managers might think they need to separate the two parts of management. Instead consider this image, where the managers collaborate.
Instead of changing the management structure, the organization can change the management collaboration.
Instead of separating leadership from serving people, integrate leadership and serving at all levels.
I would even double-down on collaboration, as in this image called “Possible Product-Based Product Development Organization.” o. Notice how this organization integrates product management into all the teams.
This kind of organization doesn't need “people” managers. Instead, all the managers collaborate on the overarching goals, and the value each team and person bring to the product.
However, all these management collaboration ideas have a big requirement: The people in the management positions want to excel as managers.
All this management collaboration is probably a new idea for your senior leaders.
Integrate Serving and Leading in Management
IME, most senior leadership teams don't realize how much they collaborate. And they don't realize that the rewards for middle management often pull those managers apart.
Instead, when you focus on management collaboration, you integrate leadership and serving. And you can reduce management decision time.
Create a harmonic whole for management, not just teams. (Part of Practical Ways to Lead and Serve Others.)