I don't know how it works where you live, but here (in France) with public healthcare the government will have to pay your medical bills after you get an accident
Or maybe there should be an exception ? "if you crash without helmet, you won't have healthcare. Take your responsibility"
Same with cars : you are adult enough to decide if you want to buckle up, but the whole community will pay for your "adultness" once you end in a wheelchair...
Wasn't there a similar debate with football a few months ago ? players get more long term injuries because they have an armor and feel safer, dress them as rugby players and they will reach 70.