The idea is to persuade car drivers onto bikes - then if they have to wear a helmet they might switch to busses, but it's more likely they would stay in their cars.

I'm not going to take my helmet off either - but if a change in the law converted 10% of the cars passing me to other cycles I would be happier and safer.

>Did car drivers stop driving cars because seatbelts were made mandatory at some point

Unless there was an alternative MORE deadly form of transport they could adopt it doesn't matter. If they said, "I'm not driving with a seatbelt - I will drive my jet fighter to work" it might have had a negative effect on accident rates.

[1] The research was by an ex-collegue of mine at UCL. He also proved that drivers give blonde women more space. Although since he did the field work himself (in a wig) he couldn't discount the chance that car drivers gave more space to very unconvincing transvestites! ;-)