It probably also has to do with the fact that most of the work is small contractors, many without even a business license or insurance, or even just the homeowners themselves. Ironworkers deal with big structures where the financing demands large business entities and therefore usually unions, both of which are typically fanatical about worker safety.

Also because a lot of them are of the "hardhats are because we live in a nanny state" and then fall off a roof or fall backwards on the ladder, because they are fabulously un-self aware, DAD