Comparing the markup on a twentythousand dollar car and a hundred dollar helmet is hardly fair. Markup on accesories is between 67% and 100% so $50 cost= $83.50 to $100.00 retail price with a profit of $33 to $50. Even a 5% markup on a twentyG car nets you $1000 and, while it depends on the person, I have spent more time selling many a person a $40 helmet(profit:$16-$20) than I spent buying my last car.

P.S. If you don't think a helmet does any good, have somebody whack you in the head with a baseball bat with and then with out a helmet on. Compare results.