Obviously, Geico plans to sell insurance in California, but just not with real people manning real offices and - presumably - taking real checks or (worse) real paper money as payments. Better to just go online, and use your debit card to use electronic blips to pay for insurance that itself is issued in a policy of electronic blips.
Why maintain those costly store fronts with real people?
And, should you have an accident, you can call their customer-non-service hotline, talk to a really friendly representative (if you're lucky enough to get one) in Mumbai or Calcutta, and a robot in Sacramento (if you're unlucky), who will send out a robot agent to assess the damage to your vehicle...and....
... well, you get the picture.