My school is new and I'm part of the first graduating class. I know of one other person (friend of mine) that matched to programs in California. I know of plenty more were interviewed or were offered interviews, though I'm not privy to their rank lists (except one...and their rank list was not strictly CA > other states).
The reason CA is competitive is because the competition starts from the very bottom.
CA residents tend to come from CA schools because you have some of the most rigorous pharmacy programs in the state (UCSF, USC, UOP) with difficult admission standards....
...they have difficult admissions standards because they choose from some of the top universities in the country (Berkeley, Stanford, UCLA, USC)...
....and those students at those undergraduate levels represent the top 5% of students in a state that has a population larger than most countries in the world.
Not to mention that a) clinical practice in CA is "different" from other states and because of that b) you want students who "grew up" in that environment, and c) you tend to prefer WHO you know (example: that student rotating at XYZ hospital really had what amounted to a 6 week job interview vs. someone out of state).
You also have a critical mass of students such that a program can pretty much fill its interview calendar with good candidates all within the state. Pharmacy is a small world and incredibly local, local candidates tend to be well networked in that locale. Programs can, but usually won't do this 100%, because being a good program means looking at other candidates just to know what's out there. Given time constraints, it's understandable why a search has to be narrowed.
So, it's multifactorial and partially subjective. Word of warning, this post had a lot of opinion that's open to discussion. Good luck to you.