The first issue that springs to mind is the funding. Most funds in California do not stay local, they go to Sacramento and are then distributed out. If you're thinking that is a system ripe for abuse, then you are correct. The formulas and methods for determining funding aren't easy to grok. But then you add in all the fraud from schools themselves and you get a real mess.
Further, Prop 13's starvation of property taxes has also contributed to the lack of public school funding in California. It's a bit of a winding tale there, but suffice to say, less taxes means less good schools. Then again, Prop 13 is, just, hoo boy. What a total long standing mess.
So, does California need better education. Oh heck yes. But fixing that requires dealing with things like Prop 13 and other huge political monsters barely hidden under the rug. Try finding any politician with the bravery, let alone stamina, to fix those titanic underlying issues (pun intended).