Being able to put up more points doesn't mean he's a better point guard. It's all about being able to set up teammates for easy and comfortable baskets. I think Prigs does a better job distributing the ball quickly in order to find the open man or the best player on the court.
Lin = better scorer
Prig = better passer = better PG
He's done it for years and years in Euroleague basketball, and has been the starting PG for a very talented Argentina team in FIBA and the Olympics, I think its safe to say that he's got more skills as a PG than Lin, who I admit still has a lot of potential for improvement.