@evan I think it's much harder to have in a capitalist society, but I think the key is what competition actually gives you. The reason we often see competition as necessary for the open web (at least in my mind) is that it is a motivator for corporations to innovate and be (at least somewhat) good to their users.
But even in the absence of competition, if good-faith users and developers are in a cooperative together, then you get these benefits automatically. For example, we wouldn't necessarily need competing browser engines if we had one that was produced/maintained by a well functioning cooperative of users and developers.
However I recognize that "good-faith" and "well functioning" are doing a lot of heavy lifting here, which is probably why we don't really see this happening