Biologically, as we age, we don’t perceive sounds the same way

In 2015, Oliver Bones and Christopher Plack, two neuroscientists of Manchester University and the Chinese University of Hong Kong, released a study called Losing the Music: Aging Affects the Perception and Subcortical Neural Representation of Musical Harmony, that explored the effect that aging has on hearing.

They found out that the brain's ability to distinguish between certain sounds diminishes as people get older, which may explain why the elderly tend to engage less with music.

So to older people, newer, less familiar songs might all “sound the same.”