naysayers to accept that this team is really good, not just "Punching above their weight."

Are you saying they'll say the same thing even if BYU wins out? You might be right - it would be more consistent, your logic is sound. What if BYU wins a playoff game? College Football Championship? Will those critics still say they are lucky?

I don't think they'll do any of those things but I already believe, like you, that BYU is winning because they are good, not lucky.