The IETF runs extensively on a concept called "two-in-a-box" --
where two people are jointly responsible for most functions.
This has some benefits, but it actually takes considerably more
combined work than having a function run by one person (because
of the need for the two to communicate), and things happen
slower.
two reasons for doing this is because single-person functions have led to
single-person "empires" (Marshall Rose and the NM area was the most blatant
example; John Moy has been accused of the same thing wrt OSPF; he's now got
2 co-chairs, but still gets accused of it), and because we've had numerous
instances of chairs dropping out on relatively short notice (or with no
notice).