The global monoculture of BS commercial music is a new development in the 21st century.
Peoples and cultures used to have a huge variety of music and styles all over the world, even if "accessibility" to it from the comfort of ones home outside a specific region wasn't cheap/possible.
>If you don't like the 'Top 20' then I presume you listen to alternatives. How did you find them? The internet perhaps?
Doesn't really matter, as culture is not what people consume in private, but what most consume and influences their public discussion. Some obscure artist I only share with 10K or 100K people might as well not exist culturally.