Great post. I live in CA too and work on environmental issues. Here is another question to ponder that might help: "What happens if we don't go 100% by then?" Imagine how screwed this planet will be if Californians, Americans, and everyone else are still driving gasoline powered vehicles and burning coal and natural gas in 30 years! I think the answer to many of your questions lies in the fact that solar, wind, and storage costs are plummeting and will continue to do so as they see benefits in scale and further technological advances. I've got a couple recent posts up that show renewables are the same cost or cheaper than coal and natural gas in many locations. Once power companies realize that, they will install renewables at an amazing pace. We don't all need solar on our roofs (though I'd love to see that) to get to 100% (and people or landlords are free to lease solar or allow companies to install solar on their roof).

Humans are terrible at truly understanding exponential growth. Wind, solar, and battery storage adoption are growing exponentially. They could go from a few percent to totaling 100% of our energy in 3 decades easy. If renewables are currently 10-15% of CA energy and have an annual growth rate of 10-15%, that means 4-5 doublings in 30 years which would get us to 100% even if consumption grows.

Something similar will likely happen with electric vehicle adoption. Once people realize fuel and repairs are cheaper with electrics they will choose them. As more people choose electrics, the cost will drop. I also think self-driving technology will lead to fewer people owning cars. Recent surveys have shown something like 10% of car owners don't plan on ever getting another car.