People Twitter

In the US, most states only require some variation of liability-only auto insurance, which basically says if you cause an accident that is terrible for another person, someone will pony up some money to give them financial restitution. This is practically necessary to avoid situations where drivers risk facing financial ruin for other people's mistakes when the at-fault driver can't pay. Expecting every driver to have a reserve of cash sufficient to cover potentially multiple totaled cars in an accident they cause from the moment they start driving is not feasible.

Beyond that, you can generally use your own savings to cover your personal financial loss from accidents. If you don't already have a decently sized reserve, it's probably best to have some more comprehensive insurance until you've built up enough to mitigate early risk. I think most people would choose to just use comprehensive insurance indefinitely and not worry about it rather than needing to pay for insurance while also building up their personal reserve. But if you can afford to build your personal savings and aren't prone to accidents, self funding would likely save you a lot in the long term.

Insurance is basically a way of spreading out risk. It or some similar system is basically required when people are constantly risking a huge amount of personal wealth, not to mention death or permanent disability.