If somebody wants to make his project in own way, why should it be decentralized? How to control ways and quality?

Everything has its limits. Perfect decentralization of development lead to a libgen collapse which not many know about thinking that it's bigger servers are still a real libgen. They are not and are mimicking libgen after capturing its vital parts. This happened exactly due to idealistic views that development can be entrusted to different anonymous individuals without regard to centralized management.

Decentralization implies loss of control. While it's good for results, it's very destructive for development and team building.