“Classic rock” and classic rock radio is an extension of what was known as AOR radio formatting in the late 70s/early 80s [AOR= album oriented rock].
AOR program directors back then were almost always white men who thought their listeners wanted a radio rotation with a similar demographic, and generally played music by mostly white male artists in the rock n roll vein. They would also seemingly play “Stairway to Heaven” on the hour for no real reason. And were obsessed with the band Boston.
MTV was founded by people who previously worked at top AOR radio stations which is why it was a rock oriented TV station AT FIRST, though once they realized that hardly any classic rock bands had music videos, they were forced to play videos by unknown British art bands who wore makeup and weird outfits to fill the 24 hours in a day.
Which is why new wave/new romantic/synthpop took over in the 80s and things got interesting again.
By 1983 MTV was basically forced into playing music by black artists, mainly because of Michael Jackson and CBS Records. Until then they didn’t play any black music unless it was jazz or rock oriented.
Classic rock radio has gotten slightly better, I occasionally will hear new wave stuff like Blondie, The Pretenders, and Elvis Costello, sometimes the Clash. Never anything with synthesizers unless it’s in the prog-rock vein or maybe “Owner of a Lonely Heart”
Current classic rock radio stations mirror these narrow-minded attitudes of only grouping certain bands in the classic rock genre, leaving out all bands who are synth based, glam rock, funk based, or dance oriented, and that’s fine and dandy.
I think a lot of why these bands [the New York Dolls, Roxy Music, Slade, Sweet, Adam Ant, Duran Duran, Gary Numan, Ultravox, Japan, Spandau Ballet, Simple Minds, and T Rex] aren’t allowed in the classic rock radio world is because the male program directions were not comfortable with the makeup and the femme qualities of many of these musicians, but maybe that’s just me.
We have to remember that even someone like Bowie didn’t become a mega-star in the US until his 1983 album Let’s Dance [his only real ‘hit’ in America in the 70s was “Fame”, which was a disco track basically]. His 70s output was still considered fairly fringe in America. Now obviously, classic rock radio plays Bowie a lot, but I think at a certain point in the 80s, he became so big they kind of had to. But Bowie was not considered classic rock in the 70s in America AT ALL.