Honestly the price of a helmut is based on what the market will bear and is also adjusted by the research that goes into the helmut.

I actualy agree with rev, a motorcycle helmut for $400 covers more but is actualy simpler since they don't worry about weight as much or ventilation or even aerodynamics. Which they do take into consideration when designing a bike helmut. Now is that extra bit of ventilation and weight worth the extra $100? THat is a personal decision, if you are like Lance it's worth the money to have a helmut specificaly designed for you and tested in a wind tunnel. This hobby is full of personal choices, helmuts.. pedals.. clothing.. frames.. forks.. tires.. you could make the exact same argument about almost every item. FOr example why does a bike tire cost as much as a car tire? We all know there is more rubber/product in a car tire then a bike tire, but there is more then just the material costs going into producing something.

A porsche uses less metal then a Ford F-150 pickup truck so it should be cheaper right? This might be a extreme example compared to the helmut but still along the same lines.