At one point (years ago), pilots in the offshore industry were discouraged by aviation advisors from wearing helmets (and virtually none wore them). For the reason being, if the passengers saw pilots wearing a flight helmet, they'd want to wear one also. Meaning, one provided to them for free and not bought by them. Easier for pilots not to wear them than supply one of correct fit for each passenger. Anyway, that was the thought process.
The budget
Gulli, the budget. At $850 a pop they were not about to buy us helmets. They did relent to the extent you could wear one you had purchased yourself. I believe they later reimbursed crews who purchased one.
Re helmets I'm reminded of a story told at the sim. S-76 crashed for reasons I forget, and ended up rolled somewhat to the left, making it difficult for the co-pilot to get out. Captain exited and helped others to extricate the co-pilot, 45 minutes after the crash the Captain collapsed and was not able to be revived. When the aircraft hit on its left side his head had hit the broom closet inflicting an injury that was not readily apparent. Then there was the 412 in Alaska that had a blade pitch link separate and the vibrations put the crews heads through the overhead window, along with being bashed against the door pillar, fortunately wearing helmets. Me? I'd wear a helmet from choice and did wear one in the offshore in the latter days, I spent the $850. Good friend flew a Beech Baron into the side of a hill at night, was not wearing the shoulder strap and head hit the instrument panel. Bled to death and his body still warm when the wreckage was found six hours later. Held the round the world speed record in the Baron for a period of time.
A brain surgeon lecturing on road safety was of the private opinion that helmets should be worn in cars, for that was the source of the majority of his income. Could you see that becoming mandated? Not likely. The choice is yours when defining the level of risk you are willing to accept. A USAF pilot who got badly burnt following an overrun in a T-33 made a career of lecturing crews to wear natural fibre clothing as he had suffered badly from synthetic fibre burns. It's the little things that can change your life for ever.