Q: what happened to itunes radio on AppleTV?

What model of Apple TV?

tt2

I've noticed the same issue on my 3rd generation Apple TV's.  I am a subscriber to Apple Music.

It is on my 4th Gen Apple TV.

Yes, that is as expected, iTunes Radio is no longer available on Apple TV 3.

tt2

The service known as iTunes Radio was ad-supported. Since Apple has scaled back their iAd network efforts, they pulled ad-supported radio. The only way to get iTunes Radio (now known as Apple Music Radio) is to become a member of Apple Music.

Once you're a member of Apple Music, you can access Radio on supported devices like iOS, Mac/PC with iTunes, and Apple TV (4th Generation). Apple TV (3rd Generation) doesn't offer Apple Music at all (including Radio functionality).