When was pop music not commercial? Isn’t this basically the definition of pop music?
It's art when it moves the needle of what we think "commercial" means.
I think the more salient difference is that folk music is accessible to produce (simple, common instrumentation). Pop music is accessible to consume (catchy melodies, danceable beats). One could say these traits co-evolved with the contexts the genres serve (cultural tradition vs. commercialization).
"Folk" I think also carries the connotation of traditional instrumentation and musical style, whereas pop is allowed to evolve. I'm not sure whether there's an umbrella term for music in modern musical style with accessible modern instrumentation.
This is a very good point. I think it would be like folktronica or indie folk or neo-folk or something else that's considered a folk subgenre.
Of couse some of the music produced like this was great art.
Frank Sinatra was probably close to the original "Boy Band(tm)". Singers were originally an appendage to the orchestra who was the big name. With TV, being young and attractive became much more important than the music and that equation flipped.
Sinatra, Elvis, The Beach Boys, The Beatles, etc. All of them relied on being "boy bands" to spread their music initially. Sure, many of them became more sophisticated with time, but much of their initial catalog was ... extremely derivative. There were a bunch of contemporary groups who sounded just like Elvis, The Beach Boys, The Beatles, etc.
Without being Boy Bands who could move records, they never would have lasted long enough to get better and become the legends we now know them to be.