IIRC the overall prevalence of hearing loss is has not been changing that much. There are a couple of opposing forces at the population level.

Most common hearing loss is age-related and the population is getting older.

Two other common causes are exposure to loud noises at work and infections. Work-related exposure is decreasing as fewer people work in heavy industry and hearing protection has become almost universal. Infections have also decreased with better hygiene and health care.

I don't know of evidence that loud music is actually causing hearing loss in young people.