Low inventory can work to your advantage because you can later sell for a high price so using that as a reason to not invest in California misses the other side of the coin.
That said, the high barrier for entry in this market makes it very hard to get started, especially if your from Newport Beach where I'm pretty sure the prices are quite astronomical. The way I see it, buying a place here to live in as a home can potentially make sense, but as a place to start off your investing career . . . it does not. I'm sure there are strategies that still exist to make a buck, but man is this area saturated and competitive!
There are financial instruments with better returns and less established risk. I for one do not want to gamble on my own or borrowed money in the mid 6 figures range, take on unknown risks that I have yet to understand (if you haven't done this before), for a paltry return. If it's possible to test the waters first with a smaller amount to understand first hand the risk, better to do it that way.
So is it a foolish time to get in California investing? I think so due to the high cost to start, that failure can put you back quite a few years, and there exists other decent (non-real estate) alternatives to invest in.