It's predicted that the new format will not go into effect until 2023. BYU has a good feel for independence and the other conferences and how that relates to their future in not just football but all sports.

Its too soon at this point to make a decision and most of the conferences including the AAC are most likely not ready to make any changes yet with this new information.

It is possible this new system will cause some of the P5s to look seriously at adding teams as well. New format is not even approved yet. Though it looks most likely, all the details have yet to be decided on.

Even without a conference BYU will have greater access than they do now. You need to consider the schedule and recruiting. Would BYU receive as much exposure in the AAC? Would they be able to recruit as well playing the teams in the AAC vs a independent schedule? How would BYU fit in the AAC? Not just in football but all sports? Travel? Playing on Sundays? Cost/revenue sharing? TV rights?

The ideal would be P5, if it turns out that will not be a possibility BYU will look long and hard at all the options available and make the best decision for the program going forward and Tom is being very proactive with this. There are not many unknowns anymore. There will be Hyper focus with this window that is opening but need to see what transpires as more details come out.