I thought I will wrap it up for you, so here are all things that you miss when companies debut GG's with 3/4/5 members:
Company is saving on:
- accomodation and living cost - Idols are people, they need to eat, as well as use water (bath)/energy (electronic devices)/other supplies
- outfits, styling,
- individual sets in MV's
- album production cost - here comes everything from time in studio, through making photographies, and printing photocards, photobooks, etc.
- travel expenses - pretty obvious
Additional things:
- don't need to hire tons of people to work with them - group with 4 members can have just 1 manager, 1 driver, less security,
- if group would flop or some members have conflict it's easier to disband them - CEO can always say that this was experimental group debuted between 'bigger' (by number of members) group debuts, but apparently format failed and they couldn't attract public
- same with contract extension if three members want to continue and sign renewal, but one doesn't want it, then all is for company to decide about their future because 3/4 never would be 4/4
- you can do MV which is 120 seconds long and still say that screentime was equal and lines were distributed well so fans shouldn't complain
- medical & health - also less 'demanding' when group is smaller
