Why do we stop listening to new music as we get older?

Who's 'we'. Personally, since I've gotten bored with assembling the latest/greatest audio system and have maxed out set up of what I have, what's left but music to explore? :-)

Many stop listening to more contemporary music because they are just not interested in exploring past what they already know and like. Nothing wrong with that.

In my own case, I like to hear contemporary music and I am behind by many years on way too much, but that's on me, not on the contemporary music being created. And also, there is just so much more of it than there was a few decades ago! 

I think the advent of streaming services has indeed helped to expose older listeners to new music…That’s been my experience at 66 yrs. old anyway.  I recently put together a playlist on Tidal that I entitled “Modern Music that Paw Paw Likes” 😂.  No hardcore Rap is represented there I’m afraid but one of Lady Gaga’s latest albums is there as is a couple of hours worth of tunes I took a shine to while perusing Tidal’s “New Arrivals” category….I can’t remember the other artists names to save my life.  Another aspect of this is that, thru music streaming services, I’ve learned (slightly to my chagrin!) that I’m a fan of Jazz, first and foremost, rather than the half-ton-stack of the Pop/Rock music I amassed on physical media pre-streaming and which I grew up with.  My theory is that being limited to physical media vs having access to a streaming service plays a significant part in whether one gets “stuck” in familiar musical genres.

I listen to a lot of new music via a great local NPR station (over airwaves).

Streaming services have also helped me discover old "new" music. Especially, 70’s soul and funk.

Streaming has opened my eyes to new music and artists I never would have heard, it’s a whole new frontier.