In principle I agree with you, but the problem is is that the gov't will pick up costs for the uninsured via Medicaid. You'd have to both let the insurance chips fall where they may AND get rid of gov't handouts for the costs not to get passed back to the taxpayer.
LQ, a rider who wears her helmet and, while opposed to helmet laws on principle, realizes that under the current system we'll all end up paying for helmetless accident victims.
Just a WAG, but I would think that the average injury cost for someone wearing a helmet would be higher than for someone not wearing a helmet. Which costs more, after all--treating someone who wears a helmet and breaks his spine, or treating someone who doesn't wear his helmet and gets killed outright?