If Notre Dame had joined the Big 10, we'd run down their #3 ranking faster than a priest after a choir boy. They'd be a .500 team in the Big 10 year after year, and they know it.
If I did my math correctly, we did catch Texas the first year in the Big 12. We were 4 behind, and won 9 more games than they did in 1997. Unfortunately we gave it all back and then some in the 2000s.