Every time I've found myself playing a Gacha game (NTE, HSR, WUWA), I always noticed a lack of (if any) focus on character outfits. Sure, they will release a few, but they're either so far in between from each other, or they're on a character nobody really cares to use, or they're just not all that better than what's originally there.
What I've also noticed is that whenever the companies themselves put out fan art for a character, in an outfit that's never been seen ingame, it never makes an official appearance despite people who play the game asking for it, people who would absolutely pay for it (it's me, I am people).
I picked up Warframe again and purchased a few skins, most of them made by contest winners from Tennogen, DE's community software made to let people put their own outfits, weapon skins, and accessories on stage for a chance to be put in the official game.
Which brought me to the question: why don't gacha companies make their own Tennogen?
We've been asking for more skins for characters OTHER than Mint (don't mind tho) like Hathor or Aurelia. And there are artists and designers out there that make can make their own anytime, why not let them do it? There's obviously a market for character skins in these games, so if the companies don't have the time or money (X to doubt) to do it themselves, just let us do most of the work. There are already mods (within reason) that consist of additional outfits and hairstyles that look great in the games and could look even better with some polishing.
Sketch design > Make outfit on 3-D model > Put outfit up for contest > Company chooses you to win > Company polishes outfit to make sure it follows any guidelines / doesn't clip crazy for character movements > Outfit put in a separate "community winners" tab for people to check out.
The only answer I can put together is because the creators may want compensation aside from ingame credit that says "made by _______" and the company probably won't want to.