I can understand the teams reluctance to doing the Rancor Keeper as one of the tiers before. You look at all the previous stretch goals and it's easy mold reuse except for Luke supposedly since he's a new tooling. No matter what the Rancor Keeper is a new tooling, and not one that will pay off long term as he's one of the few fat guys in Star Wars. He's pretty much a one and done molding. Where as even if Luke doesn't share parts with anyone, it's still Luke. That specific tool is probably already slated for the 40th RotJ line inevitably coming on normal packaging. But it could also be reused on a Mandalorian card later, or many other reuses because it's a version of Luke and Luke will sell. Rancor Keeper is a one scene wonder. He's got one real good appearance and that's it. I feel if he was put out at retail you'd have the collectors snatch up the initial amount ,but the rest would shelf warm like crazy. The only potential reuse of the mold I could really see would be a pre-cgi New Hope Human Jabba from the Falcon scene that the Special Editions added in the CGI Hutt, and that's a big stretch.
But then again, This would be the ideal time to include him no matter what. The Collectors get the Rancor and Keeper in the same set makes all the sense in the world. Even if they never use the mold again, it's served it's purpose. They could always do a Jabba's Palace pack later if they wanted to get him out if demand picked up again and include other scenery characters along side a Boba Fett or something. It's not impossible to make him work for the line but it's obviously more than the team wanted to put effort into.
Heck the Sentinel and Galactus Haslabs make this look a tad silly. Both included figures outside of the main dude who had new tooling. Granted the Prime Sentinels are very basic retooling of a basic body mold with specific head tools, and the same could be said for the Frankie Raye Nova who is just a Female body sculpt with new add on pieces and head. Surfer is straight up reuse. But then you get Morg for Galactus who by the look of it is almost completely new tooling. And really who even knows who Morg is? He's a herald of Galactus and that's about all I know. I'm sure there are those in the know who do, but I don't imagine there were a lot of people yearning for the figure until they saw him and admittedly saw how cool he looks.
RK really doesn't even have the Coolness factor. He's basically there to be a Rancor Accessory to even begin with. Anyways I gotta head to work. There's my long winded thoughts for the day.