Edit: as pointed out below, these numbers are for type 1 and 2, so the population is requiring insulin is much lower than this.

Among the U.S. population overall, crude estimates for 2021 were:

• 38.4 million people of all ages—or 11.6% of the U.S. population—had diabetes.

• 38.1 million adults aged 18 years or older—or 14.7% of all U.S. adults—had diabetes (Table 1a; Table 1b).

https://www.cdc.gov/diabetes/php/data-research/index.html

Sure, the majority of folks don't have diabetes, but come on, this affects a huge number of people, and I would bet that a vast, vast majority of people at least know someone with diabetes.

And yes, those are national whereas this is California---but it's also about changing hearts and minds. When someone from Texas, struggling to pay for their kid's insulin, learns about this, they might just question some things.