Keep in mind that Tom Osbourne, Nebraska's former great coach, couldn't beat Barry Switzer when he was coach of OU either. He went on to win some championships after Switzer was gone.
While I am not always happy with Mack Brown, I do respect the stability he has brought to the program. Hopefully he can take us to that next level soon. He hasn't even won a Big 12 title yet. If he doesn't watch himself, though, he might suffer the same fate that John Cooper of Ohio State did.
Cooper couldn't beat Michigan (I believe he was 1-8-1 against them) and was finally canned because of it. The next coach came along and won a National Championship for them a couple of years ago.