Is there any example of a successful large open source project that's truly lead by the community, and not a handful of people that decide what goes in and what doesn't? What would such a model even look like?
I think the key component of such a model is a clearly communicated method where the community can participate in the project direction, and evidence that the method is being respected. It's been brought up in this thread but Rust's governance/RFC process comes to mind. https://www.rust-lang.org/governance
In theory yes, in practice though, there's a lot of projects where the lead maintainer has vanished or doesn't spend a lot of time on it anymore making the future of the whole project and its forks debatable. Most forks aren't interested in taking the lead. The only exception I can think of was the nodejs fork, IO.js, which ended up being more of a political move and a kick up the arse for the Node team. A similar kick was given to the NPM team when Yarn started making waves.
The Rails/Murb drama a few years ago is another good example I think. A bunch of people decided they didn’t like the directions Rails was going in, created a competing framework, and after proving the concept was sound ended up introducing a lot of the unique features back into what became Rails 3.
