The allure of a big program with lots of attention and the $$$ of NIL makes for a pretty strong reason for a high level athlete to want to leave. If you want to monetize your abilities then it really makes sense. Being as athletic as your basic rock I have no idea if the idea of team loyalty has much meaning compared to playing at the next level and, perhaps, having the NBA give you a really good look.
Not possible for any of us to say why so many players left last year. I can only speculate that most of them were not getting enough playing time. The exceptions being Manjon and Fuller. We've already speculated that Manjon wanted to see how well he could do in a Power 5 Conference school and Fuller was a grad transfer.