For instance, the core research and development team for the Qiao Algebraic Geometry Research Center comprises over ten people who, during their time at the school, can hold teaching positions at the School of Mathematics. But their affiliations are not with the School of Mathematics. Even when they decide to leave, the School can hardly keep them.
They are willing to stay at Xilin now because they want to follow Qiao Ze.
If Qiao Ze really leaves in the future, these talents won't be determined to stay at Xilin.
Even for someone like Xu Changshu, who was brought in as a top-level professor, there's a high chance Xilin won't be able to retain him.
Don't think he was dead set on coming to Xilin initially; when he left, it's said he even had some minor disputes with Yanbei.