It's not correct to say that the bus factor of SRFI is one.  I'm the editor at the moment, but everything that has been done since the beginning of the process, in 1998, is available on public servers, including the full version-control history.  I've made sure that even the backups of the email archives will be made available if something happens to me.  I have written up the details of the process I follow to supplement the SRFI process document, and plan to publish it.  And a bunch of those details have been automated in srfi-tools, which is publicly available.  It's true that another volunteer would have to be found, but needing to find a volunteer is not the same as having a bus factor of one.  Finally, the SRFI process has been run by many different editors over time, so we have proof that we can transition from editor to editor.

It's also not correct to say that the bus factor of R7RS Large/Working Group 2 is one.  Everything there has been done in public, too.  Furthermore, we just made the transition from one chair to another, so we have proof that we can transition there, too.