He has told me on many occasions what BYU was like before LaVell arrived and how it was relatively easy to get admitted. There have been 3 factors that have contributed to the rise of BYU's academic profile, and they occurred sequentially like this:
1-LaVell Edwards football program brought notoriety to BYU nationally and made it a school many more LDS kids wanted to attend.
2-Increased Church membership made it more difficult to get admitted.
3-Skyrocketing tuition rates nationally made BYU especially desirable for kids with high academic credentials.