They want Yujin out of it, that's all
Adding on that Gaeun was technically confirmed to make it, the only shocking one was Samuel, but he suffered from the Bora edit where they didn’t show any growth for him, and Jonghyun has been fishy for the way he dropped but Pledis would have wanted him back too. If all of Nuest debuted, I don’t think Nuest as a group could have been as successful.