When I was a kid, we didn’t wear bike helmets. No one did. I don’t even remember seeing bike helmets sold in stores. We also didn’t wear seat belts in cars. We were idiots.
Today I wear a seat belt and use a bike helmet. It never would occur to my kids that people don’t do both of these, all the time. And that’s a good thing. But there are still non-believers out there, I guess.