i don't think it's as much an issue of organizing around that new person as it is organizing around the new home for the software, regardless of who is maintaining it.
if i want to update my installed version of net::ssh, can i go to the project's homepage and download a new version or do i have to look through a dozen forks on github to find out which one looks to be the most maintained and hasn't broken anything?
Even if no one steps forward, would that be so bad? Capistrano works perfectly well for the vast majority of folks. It's not like I'm leaving behind a legacy of mostly-broken software. :)