Exactly this ⬆️
20,22,24 could all probably work but there is certainly an ideal max and 30 is likely well over it. Especially when it's 30 in the 3rd best conference. Best case XII has 6-8 ranked football teams each year. That leaves a lot of unranked content that isn't paying for 30 schools. Iowa State at Washington State @ 10PM on a Friday night is not exactly must see TV.
If XII were to go to 20 now, there's probably only 4 seats left at the XII table (5 if KU is poached by B1G). UConn would have to beat out multiple ACC leftovers to get to that 4/5.