The free market oil company's in California the third largest producer state with 16 refineries have colluded to give us the gasoline prices that are at least 20% higher than the nation. I guess that what you get if if you are the fifth largest economy in the world and have a free market with little competition and good lobbying.
Your synopsis is not correct. California specifies a blend of gasoline sold no where else, so unlike the rest of the country it is not a national market. According to your state government only $1.24 - $1.40 per gallon are in refinery costs.
www.energy.ca.gov
And the state website doesn't bother to mention the notorious carbon cap and trade program, which is paid by the refiners, so it raises their costs:
The Cap-and-Trade Program is a key element of California’s strategy to reduce greenhouse gas emissions. It complements other measures to ensure that California cost-effectively meets its goals for greenhouse gas emissions reductions.
ww2.arb.ca.gov
The Wall Street Journal said it adds 24 cents per gallon to gasoline costs, and other states don't have that tax.
Then there's the low carbon fuel regulation (it encourages refiners to use biofuel). If a refinery can't meet it (none do, apparently) they have to buy regulatory credits that the WSJ says add 22 cents per gallon of cost. And if you look at the ca.gov numbers you don't see that tax as a line item, because it's also in the refinery cost line.
And, while California's population has continued to grow (until 2022, when it shrank a bit), no new refineries with large capacity have been built in the state for a long time for two reasons. One, environmental regulations and land costs make building a new refinery very expensive, to the point where energy companies are just unwilling to take the risks, because two: California has passed a law, as you well know, that restricts future ICE vehicle sales, so the gasoline and diesel fuels markets will shrink. Smaller markets attracts less investment.
As for your lobbying comment, I've never seen a less effective lobbying effort than oil companies and refiners have in California. If their lobbying was any good they wouldn't be staring at laws that regulate them out of existence in the long term.
As far as I'm concerned, California has the gasoline market it voted for. I know, I lived there on and off from 1988 to 2018.