But either way, the platform is not really controlled by the community. Sure you can file issues and pull requests or even fork Chromium but ultimately, Google still controls what's merged into the global Chromium master, so it's not really decentralized power.
Also, you've missed the main point. The problem here isn't that we don't have enough free/open source browser engines, the problem is that we don't have enough _different_ browser engines. If there's only one dominant browser engine, then whoever maintains that engine can decide how the web works. And that's kinda scary.
