Dudes transfer for a lot of reasons, including academics (change of major or struggling), coaching changes, family needs, homesick, lack of PT/perception they will not (or can not ) develop to get PT here, or coaches choosing not to renew Schollies. Or a combo of any of these. Sometimes the parting is a mutual decision in that SA's best interest.
I personally am not that worried about the guys that left because the young guys seemed a long way from getting burn and the possibility exists to upgrade through the portal. The older dudes either are grad transfers or were buried on the depth chart.
Further, it's still early and we don't know precisely WHY the young guys transferred. And we only have a partial view of whom we are getting through the portal yet.
For me I'll wait and see what we end up with before worrying a whole lot.