And staying in the business? Consider that people are living longer, even though their organs—including the ones used for hearing—are wearing out, and we haven't seemed to come up with a way to make those two facts come together. So even if you, as an audiologist, deal solely with the elderly, you will have a thriving practice and a never-ending supply of patients.
And why is that? Because the average life span of an American baby born in 2000 is—all things considered, including dying while TEXTING WHILE DRIVING…DON’T DO IT!—75 years for women and 68 years for men, while, in 1930, a scant 70 years prior to that, life expectancy for women was 49 years and 47 years for men. It’s just a guess but it's probable that when those 20th century people died, they could still hear pretty well.
And, of course, with the invention of earbud headphones and speakers at concerts designed to blow out eardrums during the first opening bars of a song, you will always have young people as patients, too.