Weird Selection Process at USC?

I’m aware of how selective USC is, but sometimes I wonder how exactly they pick their class. It seems like they take preference over people in California, given that there are much more unqualified applicants who apply from LA areas, yet around 40% from Cali apply and 40% are admitted. Also, they seem to take people from urban areas outside of California more than suburbs, and if they are suburban areas, they’re wealthy and have great high schools. Also, I know that stats are not the main part of the application because they can just fill their class up with valedictorians and perfect SAT scorers, but the profile is much lower. I’m also not sure it’s extracurriculars either because many of those top people have amazing clubs and essays. Can anyone give insight into how USC picks their admitted students?