For BYU to get into a P5 conference there has to be a P5 conference that's looking to EXPAND/REPLACE.
When a conference expands every team in that conference takes a substantial monetary loss ($$$$). No school president is going to vote for LESS MONEY.
Nothing will happen with BYU until all of the TV contracts expire (~5 years).
BYU needs a conference shake-up... they will never be 'Invited' to join.