Don't fool yourself
Life can be dangerous, but bicycling is not worse than many other things we do that we'd never consider wearing a helmet for.
For every single person in the USA who dies on a bicycle, fifty die in their cars. The ratios of head injuries to other injuries are similar. When is the last time you saw a person wearing a helmet to drive a car, outside of a race?
Working from a ladder or showering in a clawfoot tub puts you at more risk of head injury, per time of exposure, than riding a bicycle. Do you wear a helmet for those things?
Walking along a public street is three times more lethal than riding a bike along the same street. Where are the helmeted pedestrians?
Believing that a helmet is essential for cycling, but not for other things that are just as risky, is oblivious. Yes, you can fall and hit your head while cycling, and maybe, just maybe, a helmet can prevent head trauma in that case. But the same goes for many other activities that most people would consider it insane to wear a helmet for!
We have cycle helmets because they make an easy buck for helmet manufacturers and retailers, plus those organizations that get paid to promote them. So wear a helmet if it suits you, but don't be a tool of folks who have only their own interests at heart. And be sure to wear it when you go up on a ladder, or go out walking, because you need it even more at those times.