In 7 seasons as an Independent, BYU has averaged 4.57 P5 games/season.
In the 20 seasons prior to Independence, BYU averaged 2.45 P5 games/season.

With a conference slate of 8 or 9 games, it is impossible to consistently have the flexibility to play more than 2-3 P5 games per season. There's also a perception issue with being G5. BYU has been helped significantly with the handful of ACC, Big 10, and SEC series' it has landed by being classified as a P5 for scheduling purposes. In the late 1970's, BYU began to try loading schedules with more P5 games (BYU went from rarely playing P5 games, to playing 1-2 and eventually 2-3 per season). Over many years, 2/2.5 P5 games/season was the norm for BYU. That changed when BYU went Independent.

BYU's average number of games against P5 schools will continue to go up, from what we see now. Scheduled P5 games so far for the next four seasons (5.5 per season):

2018-5 (Cal, Arizona, Wisconsin, Washington, Utah)
2019-4 (USC, Washington, Utah, Tennessee)
2020-6 (Michigan State, Missouri, Arizona State, Stanford, Minnesota, Utah)
2021-7 (Arizona, Arizona State, Virginia, Utah, USC, Baylor, Washington State)