This is a topic that I spend a lot of time thinking about and can get a little confusing - but it is important, so bear with me.
This has nothing to do with age or experience in the managerial role. It has everything to do with the mindset and what you think a manager should do.
Old manager thinking is what I grew up with and was very common in the past. The manager was the expert, was in control, made all the decisions, and was seen as an authority figure. To be honest, it appears to have worked in the past, so I have no negative feelings about these types of managers. I had them and learned a lot from them.
New manager thinking is what is needed today. This manager isn't the expert (usually), teaches people how to make quality decisions, and focuses on being more a servant leader or guide than an authority figure.
Old manager thinking leads to stifled organizations and unengaged workforces. It can "work" if you define work as profitable at any given time. However, it will lack sustainability and have more failures than successes. You see these in larger companies not only because of bureaucracy, but because those larger companies have the resources to not feel the pain of the failures.
I point this out because many of the concepts like flat hierarchies, no managers, etc. are based on the concept of the old manager thinking. None of them take into account new manager thinking, which would almost universally make these concepts better.
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