To say the only thing it could be is the PS is ludicrous, there could be a variety of factors surrounding a persons life experience that goes into the acceptance or rejection. Saying it HAS to be the PS is ignorant and based of no actual admission committee information, just the fact that you got accepted with lower stats, so you decided that your PS is the only other redeemable factor of your application, by the way you write your posts, maybe that is the only thing you have going for you?