Once OU and UT leave BYU will be the highest average attendance if the 2022 numbers are the guide. BYU, despite a less than stellar schedule and a disappointing season, is still averaged 59K ber game. BYU is still 27th overall and still the only non P5 School (Not For Long) Anywhere in the top 50, and their average attendance is ahead of every Pac 12 team except USC and Washington.
I am willing to bet BYU will average well over 62K next year in their inagural season in the Big 12 with the home schedule they have coming.
The lowest average attendance in the new Big 12 will be Houston, who as of this season averaged less just under 26K. They have a stadium capacity of 40K.
The two potential new Pac 12 teams, SMU and SDSU...LOL
SMU averages just 24k per game. Stadium Capacity is 32K
SDSU with their shiny new stadium averaged 29K last season. Their new stadium holds 36K
Both of these stadiums would be the smallest capacity in the Pac 12-2+2 by a wide margin