The emacs devel mailing list is way more active than that.. although you do see some regulars there for sure.

You misunderstand. Every mailing list has their healthy share of drive-by contributions, but emacs.devel contains a handful of dudes for whom *all they do* is emacs. We're talking nights, weekends, holidays. If they were indeed working a job, the inordinate time spent on the mailing list would constitute defrauding their employer.