[Assuming good faith despite some inflammatory language.] In smaller teams everyone talking to each other and building a shared vision can be quite sufficient.

[Assuming good faith despite some inflammatory language.] In smaller teams everyone talking to each other and building a shared vision can be quite sufficient. It's indeed common to have startups that have very flat organisation, they might have a designated CEO that's in no actual way above the others. They can be plenty capable of producing amazing results despite the small team size. However such a small group can't handle larger challenges, like designing and building a commercial jet, they will need many more workers. 1000 workers can't just come together and agree on a shared vision, even ignoring the square law of communication paths just giving each person 10 minutes to present their view would take weeks. Hence, in the very least we will need some communication hierarchy to allow workers to do their job while still synchronising with relevant other teams. However, just communication is not sufficient, coordination is also important, if the jet is going to have the appropriate range, fuel tanks, engine efficiency and packing density needs to be designed to provide that range. Again, this would take quite some time if everyone should be involved in the process. This is mostly in the leadership side of course, but covers those who are attentive to the trade off between security and deadlines. It's not reasonable for the individual engineer to be solely responsible to make that tradeoff. In particular, a sloppy engineer might think security is not important at all, and another engineer might think that no risk at all is acceptable to the point where nothing can ever be produced to achieve their standards. It's leaderships role to make sure that standards are aligned between engineers so we don't get a ten year delayed jet with some key parts made out of brittle plastic. Now, managers can also have a people management role, and tom me those are the ones responsible to keep me as a worker happy and productive. They are also there to detect when some area is understaffed and find solutions to such issues, eg. talking with other teams for assistance, recruiting, decreasing scope, etc. If they weren't there, this job would fall on each individual worker, who would have to go out hunting for support instead of focusing on their actual tasks at hand.