I think folk music (with lots of repetition) was kind of always understood by more people than classical (with development and variety). But in the 20th century

I think folk music (with lots of repetition) was kind of always understood by more people than classical (with development and variety). But in the 20th century it got even more so, as the mass market for music led to folk/repetitive stuff getting a lot of commercial demand and evolving very fast. Personally, even though I've listened to many classical pieces, my musical ear is still firmly folk. It wants music that contains interesting repeated patterns, otherwise the enjoyment is incomplete.