SMU was a double digit favorite. I'm not sure how you come up with the idea that BYU was "supposed to" win that game.
I agree, that we haven't seen much yet. I'm pretty sure we don't know how good or bad this team really is. I suspect they may still get a surprise victory in the B12, as well as maybe a surprise blow-out loss.
We'll ultimately see who they are. But saying that they've won the games they were supposed to win doesn't necessarily feel like an accurate statement either. I'm pretty sure they were "supposed to" lose to SMU.