Have we ever gotten a diamond in the rough as a transfer, even pre-portal era? Has anyone? Somebody way down on the depth chart or coming from a lower division that exploded for us?
It's not impossible from high school, with the shear number of kids playing, guys developing at different rates, different levels of competition, training, etc. You'll naturally have guys who don't get noticed much and end up lowly rated or unrated. But guys in the portal have already gotten an opportunity at the collegiate level and there are a lot fewer of them than high school players so you can more easily compare their body of work.