About 20% of US GDP is social spending. What percentage of GDP will get us where we need to be? Why does California have so many notorious problems when, compared with many other states, its social spending is so generous?

Social systems are not as simple as "give people more money", particularly when millions of people have already been socialized into criminality. Thinking this is a total misunderstanding. Most criminals are not stealing to get bread to feed their family. They commit crimes because a) it's fun b) it's what their peers are doing / needed for their social standing and c) it beats working for a living. Yes, a well-socialized conscientious person would never do this except in cases of severe hardship - but that's not the reality of what's happening.