>Most states allow you to go without insurance by fronting the cash.
That's BS on it's face. Most states don't allow it or they restrict it to big business and government agencies.
>because most people have no desire to lock up tens or hundreds of thousands of spare dollars just to avoid car insurance.
Most people's money isn't making a return greater than what insurance would cost them.
Second, this completely ignores my point about credit. I can easily get hundreds of thousands of dollars in credit secured against my house or tens of thousands in unsecured credit (credit card). Why must I pay to keep the lights on at some insurance firm?
And I'm not particularly rich. If the numbers pencil out for me then surely they must pencil out for millions of people.
States' interest here is in guaranteeing that there will always be a minimum amount of money to compensate victims, regardless of what other financial shenanigans you have going on in your life. That's not a standard that lines of credit and investment accounts meet. Self-insurance is simply a terrible option for most consumers, so no one does it.