If Luke hadn't been injured in 1999, and BYU didn't drop those last couple games, Lavell would have finished ranked as late as 1999 during his tenure. It seems precarious to me to say that the game changed so rapidly in 4 years that Lavell could no longer compete, especially since BYU continued to have winning (or .500, in the case of 2000) records all the way to the end.
Lavell had 4 years of being unranked. Bronco is about to complete his 5th straight. If the game passed Lavell by in 4 years of unranked finishes, it has clearly passed Bronco by as well.
And for the record, I was not a BYU fan in the 1990's. I was a kid in Washington cheering for Wazzu, Gonzaga, and to a much lesser extent UW.