Of course it is the choice of the individual as to whether they wear a cycling helmet, but to suggest the increase in people using them is driven by commercialism is both bizarre and ridiculous!
Anyone who believes the money making potential of cycling helmets rather than their obvious protective qualities is more important needs only to see a picture of Fabio Casartelli, who sustained a fatal head injury during the 1995 Tour de France, to settle that arguement. That one terrible incident was the biggest single contributory factor in the decision to make helmets compulsory in cycle racing. Of course there may always be the odd instance where a helmet or any other piece of safety equipment (airbags, seat belts etc) may actually cause more harm, but these occasions are rare and anyone who uses such an arguement to justify not using them is kidding themselves.
We probably all know of someone who has had an accident and shown you their cycle helmet broken in two pieces. I know I do, as a mate of mine had the misfortune to (in the dark) hit a plastic mineral water bottle with his front wheel. Unfortunately it had the cap on, so did not just crush under the wheel. His bike went from under him and he hit the ground head first. He did sustain a hospitalising head injury, and his cycle helmet split in two. Imagine how much worse it could have been if that helmet hadn't been between his head and the Tarmac.