The history is also littered with dead open source rejecting useful improvements, so your criterion doesn't help either
replyThen, as the parent commenter suggested, fork the dead project.
replyNo project is obliged to accept your contributions. It's on you to market them, either to the maintainers of the existing project for merging, or to the community through a fork.
> Being able to market your work and build community are key skills for open source contribution.
replyIt's not a key skill at all, as not everyone is interested in popularity.