I don't have a clue how the selection of mods works, but I understand it can take a relatively long time between application and for a suitable vacancy to come up. Patience is a virtue on this - any call up will be a bonus.

Incumbents do a good job, spanning across all forums [the Senior Mods], via the RBP alerts. (Result: probably a very, very long list of prospective volunteers but only a few call-ups).

Lots of FT forums don't require an official moderator, but some have them, others don't. The Senior Mods pick up the slack (e.g. RBP - noted posts) for the ones without an official person.

I'm very happy with how FT is run, in terms of letting some forums self-police as much as necessary. Bottom line is that ALL forums get attention (via response to RBPs).

My experience is that RBPs of all forums, included ones without a mod, get a response within hours (or overnight at most).
This works well.
The powers at FT wisely keep a light touch as we're all responsible adults and can mostly act with decorum with our fellow FTers.

Hallelujah for that!