There has never been a music radio station that has never played a song someone does not like. It doesn't matter if it was the heyday of KFRC, Z-100 in New York, WLS in Chicago, KJR here in Seattle, there are always songs aired on their favorite station that people do not like.
I'm not saying people must listen to anything. My point is that the business of today's radio is much different than it was even five years ago. Some people choose to view how a radio station should be programmed through a set of rules from two or three decades ago.
You are right, in my opinion, there is some appeal in listening to another radio station in another city or another country. But my personal experience and limited talks with others is that nostalgia wears off quickly. We are a lazy society, we want things now, even McDonald's has tested the concept of outsourcing drive-thru order taking to places like India to reduce expenses, but primarily speed up the experience. It might not sound much to you, but when it comes to drive-thru food, seconds do count.
Same goes for a radio experience. I do not think in the long run people will do all the setup needed to hear international radio in their car. I think there are people who are too lazy or too stupid to set up their bluetooth devices in their car, whether they are paired already or not. How many newer, expensive cars have you seen out there with the driver having his or her phone to their ear?
Back to the formats: How a station positions itself is not solely from a few songs or a few artists. Like you said, there are "trending" formats. Even WLTW (Lite FM) in New York plays "Dark Horse" by Katy Perry and "Pompeii" by Bastille. They also play Imagine Dragons too. Much more than just the music.
Appreciate your thoughtful post.