a bunch of hackers behind Void Linux made everything tick on top of
runit without all that much effort.
The problem with the runit model is that it is pure supervision -
it does not provide service management. You have to run all your
oneshots _before_ you can start longruns. See
https://fosdem.org/2017/schedule/event/s6_supervision/ (15 mn video)
to understand what goes into an init system and why runit alone is
not quite enough.
Of course Void Linux manages to do it, but it is, pardon my French,
a hack job: AFAICT, udevd is not supervised, and some oneshots are
implemented via longrun processes doing nothing. This is cramming
the service management peg into the process supervision hole, and
can never be perfect - Void would definitely benefit from switching
to real service management. But so far they haven't expressed any
desire to switch.