Forgive me some exaggeration for comic effect. What we'd actually see are helmets which advertise themselves as safe, and which look safe to uninformed external examination, some (but not all) of which are very, very cheap, but any of which (and good luck guessing which ahead of time) might as well be made out of cardboard and nails, and so when you bump it your head explodes. (Alert: black comedy again.)
Instead, in the US the DOT or the CPSC (can't be arsed to look up which) says: "every helmet sold must meet this standard of safety", and then backs that up with guns. Now you're free to price-compare, with the assurance that your head won't explode. (Yah: I keep doing it! Sorry. I like injecting levity into serious subjects. Try not to get distracted.)
Consumers, acting as individuals, have negligible influence over corporate behavior, and are easily misled.
People, acting collectively (in this case as a "government", but as other collective organizations, too - including "corporations"), can stand up to other collectives and force them to adjust their behavior in pro-social ways.
Instead, in the US the DOT or the CPSC (can't be arsed to look up which) says: "every helmet sold must meet this standard of safety", and then backs that up with guns. Now you're free to price-compare, with the assurance that your head won't explode. (Yah: I keep doing it! Sorry. I like injecting levity into serious subjects. Try not to get distracted.)
Consumers, acting as individuals, have negligible influence over corporate behavior, and are easily misled.
People, acting collectively (in this case as a "government", but as other collective organizations, too - including "corporations"), can stand up to other collectives and force them to adjust their behavior in pro-social ways.