In three words:
1. Sound (phones will NEVER deliver the BIG SOUND of a TV with a sound bar).
2. Screen (there will NEVER be a smart phone with a screen size large enough to prevent severe eye strain from trying to watch videos or movies on one).
3. Audience (phones are meant for an audience of ONE, not a group of people).
I probably should have reworded the sentence you quoted, although I think a lot of people use their phone for everything.
With the younger demographics, the small screen doesn't bother them.
As for the rest of your points, you're assuming that every music or radio consumer uses a TV with a sound bar, and wants the really big sound, similar to what you get from the soundsystems that 60's and 70's music aficionados loved to install in their homes.
Today, most 'radio' listeners probably use phones and earbuds or earphones of some type. 100W home stereo systems went out of fashion some time in 2010. The Great Recession, and/or adoption of the IPhone as the primary entertainment center, did them in. Yeah, some people have the big systems. Try blasting one in an apartment some time, and see how long it is before the neighbors are slamming their fists on the wall, or the floor.
And even if someone wants to hear their music on a bigger system, they bluetooth their phone into it, and listen that way (as kwthom mentions upthread).
They don't call up a music or radio channel on their TV.
RE: Audience: increasing numbers of people listen to music and radio alone. In my metro 50% of the residences have one resident. 50% of the population lives alone. Most cars have one occupant. And when we're talking
radio, it's solitary listening for the most part. Because most people under age 45-50 don't listen on actual radios or boomboxes anymore. They use earbuds or computer speakers. Primarily GenX and older use actual radios.
And you can bluetooth your phone into a bigger system if you want, which is what a lot of people do. My Millennial friends and neighbors do that in their cars all the time. They also do it through their home systems, if they have one.
My main point is that
no one is going to buy a TV set to listen to radio. That train left the platform in 2005.
Sure, there are older holdouts. The car shop that fixes my vehicles has a boombox blasting away in the garage 24/7. But that's increasingly a rarity.