that is not a given. You assume Tanner would be as slow with his reads and throwing the ball as Taysom, and you assume the only reason the receivers are dropping passes is because of the WR. Those are not givens. Taysom is also not hitting timing routes which makes it harder on the receivers in this system.
The reality might be that if teams considered BYU's qb to be a passing threat they might not stack the box and blitz relentlessly.