Is a Freshman executing at an incredibly high level in a pro style offense vs. mostly a Junior in his third year starting in an Air Raid system.
The magnitude of that contextual difference can't be overstated.
You won't be able to see how important all that difference is with highlight videos, but it's there and it's real. Although, I don't think USC runs hardly any plays from under Center anymore, but it's still pro style concepts.
Have said it before, Goff has some very good qualities and those show up on highlight videos. He just needs to figure out how to transfer those to a pro system, which is no small task. He had crap preparation for the NFL for 3 years in college. And now that he's in the NFL, it shows.