I see people saying Cal could choose to drop football, that seems more likely for Duke than Cal in my estimation. They're not committed to football, they're not interested in football, their stadium environment is notorious for being so quiet that it's like being on a practice field. I could see them getting an invite to follow UNC in all sports but football, but I'd be surprised if they earn a football invite to the big leagues.
Everyone acts like UNC is a sure thing to go to either conference, and sure they kill it in basketball, but they're barely a middling football program in the ACC. Miami, FSU, GT, Clemson, VT, BC, and even Wake and NCST arguably have all easily had better runs in the conference than UNC over the last 20 years. It's not like they're Texas, but maybe I am not seeing how much value there is in having a strong brand with a good logo.