Here's what i know or think I know.
A free-to-play game has to limit the ways players can generate in-game wealth in order to motivate them to buy energy with real world cash, and the featured auctions, by somewhat undermining the resell value of accessories, play a part in that. Furthermore, Featured Auctions also give players access to rare accessories that they might not otherwise get, so it's a win-win for us and OOO.
The Featured Auctions are pre-programmed and are not just randomly generated. Everything that appears in a Featured Auction does so because it was intentionally programmed to appear for a reason at a certain time and for a certain duration.
It seems like there are several pre-programmed loops running concurrently.
Occasionally someone at OOO "manually", if you will, programs special items to appear, such as bombhead masks or something.
Does that sound about right?
So, how are the items that appear chosen? Why those items and not others? And what motivates OOO to make a special insertion from time to time?
In theory it would be a complex mathematical formula intertwined with the economy and the material and costume market to try and keep them stable, with human adjustments if something needs a little tweaking. In practice it's probably more straightforward, like "these are thing from old promos that were in high demand so we will sell them to burn the players' crowns and keep the CE prices from exploding to the point where people quit" and the human interaction part is "oh I remember this item that not too many people got but I like it, I'll put it in".
Also, observation: Mawa likes conspiracy theories. Eury doesn't.