For me this is all about team size. It works if you have small teams, maybe max 6 people. But anything above 8-10 this is a total no go. Because management tasks just are not able to be done well at that point.

You right, but there is a very real coordination problem above the team when you're doing bigger things. I've recently experienced an organization with approx. 25 teams of 5-8, and because of their organization they had way too many concurrent initiatives. It was very hard to effectively swarm multiple teams on fewer (bigger) projects.