Don’t think it would be more than it is now; game dev is not the same as web dev and the sourcecode of this game is very readable and easy to work with. The language is not going to be the issue for getting collaborators.
> The web version is literally just a .js file, all the code is there. Fun fact: the user run servers (my own server Myxori and Magic) run a modified version of that file. I literally download the file via inspect element, add some wrapper code for networking, and get a fully functioning server.
Open source games are not really constrained by devs, I think. I'd say that dev work is the one that's best covered in the open source game development. Project management, marketing, asset production, user experience, quality assurance, product management seem to be much more underserved.
Not having to install would be awesome. And JS would make it accessible to most devs.