I have access to the source of tons of stuff, and yet I can't fix it.
Not without spending months on understanding their codebase and going out of my actual projects and work.
(And even then, my fix might not be accepted upstream, so it could be invalidated with any major or even minor version update).
That other's have access too, so someone might fix it, also doesn't work that much. Tons of projects, even extremely popular ones like GTK have but a few commiters, and tons of open bugs.