SMU got the death penalty in 1987 and it took them decades to recover. SMU is also a fairly small church school of 12,000 students. Comparing them to super-blue-blood USC (46K enrollment), or even to big state school UCLA (47K), is pretty silly. I can't think of a small private religious school in LA with a football team, but if there were one, then that's the appropriate comparison for SMU.
The appropriate comparisons for USC and UCLA are to UT and Texas A&M, each averaging 100K or more per game.
So if you really want to compare interest in college football in Texas compared to interest in college football in California, add up the average attendance of the top 10 schools in Texas versus the top 10 schools in California.