Unfortunately, if you have a lot to lose then you need a lot of insurance, if you have nothing to lose you only need the minimum amount.
One can always file suit and obtain a judgement where the other person will have to work a long time to pay the judgement. Also once they are found guilty in one case, the burden of proof shifts to them on other cases under the theory of "Collateral Estoppel", defined as once a court has decided an issue of fact or law necessary to its judgment, that decision ... preclude[s] relitigation of the issue in a suit on a different cause of action. So it becomes easier to obtain judgements after someone is already found guilty.
So in post#40, the parents would have to sue that individual for medical costs. If criminal acts are involved, such as alcohol, the state would file criminal charges. If found guilty in a criminal case, under collateral estoppel, the guilty one can not argue no guilt in a civil case and it would be relatively easy to obtain a civil judgement for the injured one's health costs.