I think part of it could be the 9% guarantee[1] which mandates that the top 9% of California high school students be offered a place at at least one UC.
[1]: https://admission.universityofcalifornia.edu/admission-requi...
[1]: https://admission.universityofcalifornia.edu/admission-requi...
Could you explain where you're coming from?
I'd say follow the money.