Note the absence of Pac 12 teams. Under Larry Scott’s leadership, that conference has certainly gone downhill.
Two things hurt the PAC 12:
1. Their football games often start at 9 pm Eastern time or later, which means few on the US East Coast see the teams even if they're on ESPN.
2. The lack of national carriage of the PAC 12 Network really hurts viewership nationally. Note that FOX Sports has first dibs on national games of the Big Ten on the over-air FOX network or FS1 network and the SEC has their big game on CBS and also national carriage of the ESPN-owned SEC Network.