The more proactive & efficient the law is, the more confident the consumer is. Such agressive consumer protection laws encourage citizens to participate more in the economy, effectively raising the state's GDP. In addition, it ensures, the vendors/manufactures to abide by the law effectively ensuring proper quality control throughout the system.
Consumer confidence is essential to the growth of any nation/state. States/Nations which protect consumers often grow better than its peers.
So, what, if anything, is unique about California that results in
these more aggressive consumer protection laws?
To answer your question, you need to look outside of USA/EU. You will understand the problem.
People from the west/Europe do not understand any of the problem, because, you were always protected. Let me explain with an example. In our Country, you hardly get a working product, when you return a faulty product. If the product fails, the probability of getting a replacement is very low and often involves visiting the service centre in person and wait for 3 weeks to get an approval for replacement, which was officially in warranty period. (Amazon changed things in recent years). I, myself abstained from purchasing many products, which I needed and often stuck to DIY/No solutions. Spending was risky and I might end up wasting time visiting service centres and talking to idiots, who want to avoid basic service. If you dare to sue, be prepared to spend at-least a couple of years and the max the court could give you is the value of the product with Bank interest rate, if you are successful and if they don't appeal. If they appeal, Spend another 2 years in court. if you win there too, you will get your value of the product with bank interest.
Now, If I were in California, why would I be afraid of purchasing something I need, when I am confident that the law would protect me from defective products. This confidence is essential for a state/nation to grow. Such confidence puts pressure on manufacturers to produce better quality products.
States/nations which implement right protection laws often lead the pack in growth/standard of living. This encourages businesses to enter these regions to make money. Win-Win for All.
Consumer confidence is a transaction between parties, where money changed hands for any goods, services, security, etc. California had always lead the pack amongst other US States, hence they are the biggest economy. They want to continue their legacy of leading the pack, hence they aggressively implement consumer protection laws.