Like every other program, the offense lives on the backs of the o'line, not the QB. Adequate signal callers look like stars behind monster lines, while the opposite is also true. Park is probably an adequate QB by league standards. But it's how Jake Campos and the others in front of him develop as a unit that will make him better or worse than his credentials may indicate.
I mean, that's not 100% true. A good QB and/or coach can make a bad OL look better.
Tom Brady is one of the least sacked QB's in the league. He gets hurt, and his backup Cassel becomes the most sacked. Brady comes back and the same OL is magically good again. Same with rookies, they get sacked more until they get experience.
Obviously having the best OL makes it easier for everyone else, but it's not the end all be all. QB will always be the most important.