in the way you describe. Texas, USC, and Notre Dame are among the few. It is unrealistic that BYU could ever get to that level of accomplishment in the time frame needed to expect a P5 conference to make exceptions for no Sunday play.
Until then, Sunday play is a deal killer for full conference membership. Even in the Big 12 it would represent a huge hurdle.
But, you are right, there are other reasons that the PAC would not want us. They just can't say it because it would provoke a legal outcry.