It's not going to happen in Western Europe, because it is not really necessary. Most of my family and friends have used bikes nearly daily since they were three

It's not going to happen in Western Europe, because it is not really necessary. Most of my family and friends have used bikes nearly daily since they were three or four years old. I know of no-one who had a head injury. Biking without helmet is perfectly safe here (Netherlands), because of traffic laws and bike lanes.