I suppose that's true. But at least most people took their headphones off when they weren't at home, which somewhat limited their exposure time. Today, when I'm outdoors, it seems like a large fraction of people are wearing earbuds. For instance when I'm riding on the bike path, I have to be alert to the fact that nearly everybody out there who's walking or jogging won't hear my signal from behind as I pass them, because they're all wearing earbuds.