Many reasons, but here are three factors I’ve read about:
1. The overly generous COVID free money meant that for many people getting a job would mean a drop in income, this despite the rapidly rising hourly pay rates offered by desperate employers.
2. California’s generous rent relief programs encourages many to stay unemployed.
3. Mothers with school-aged children quit to take care of their new responsibilities at home, especially in the blue states like CA with strong teachers’ unions. A surprising number are deciding to not return to work.