As of now, beginning in 2024, ESPN only has BYU in the west. ESPN has decent ratings in the late slot, so I think they would still like to have a game there every week. Since they don't seem too excited about signing a deal with the PAC right now, it makes me believe they're just hoping for 2-4 teams to jump to the Big12 so they can fill that slot, but not have to worry about paying that whole conference.

ESPN does (sometimes) have games on ESPN2 and ESPNU late at night, but they haven't had very good viewership, so maybe they don't care as much about those.

I was looking at the schedules of the PAC teams and BYU over the past couple of years and everyone had 2-4 home games that started at 9pm ET or later, so you'd probably need at least 3 more western teams in the Big12 to be able to have a game every week late at night on ESPN. That's assuming that the Big12 late games end up on ESPN and not FS1. Late games on FS1 don't seem to have near as good ratings compared to ESPN. I'm hoping that B1G and MWC games always end up on FS1 leaving ESPN for late Big12 games.