A good BYU team should beat a bad Tennessee team. I'm not sure we have a good BYU team, and I'm not sure Tennessee is as bad as they looked last week.
More than anything I'm responding to your line from the initial post that "there is nothing at all respectable about Tennessee and there hasn’t been in a very long time." That's false. They're not great recently, but they've been plenty successful between now and a very long time.