My first thought: can this possibly be solvent? There are apx. 32 million adults in California. Are there $32 billion spent per month in-state on things that aren't those common categories?
Then I realized that this includes business purchases. Everything sold in California would become 10% more expensive. There'd be a huge incentive to buy from out-of-state, and a huge disincentive for out-of-state purchasers to buy from California merchants.
I also wonder what it does to the population/demographics over time. If you're poor in another state, there are 12,000 new reasons per adult per year to move to California.
Including B2B purchases, could the current California economy absorb $32 billion per month in additional taxes? Even if it could, this would pervert the economics of the state so badly it's hard to know what the effects would be over time.