Why is my 14 year old niece now collecting vinyl? I can guarantee it's not nostalgia. There's obviously more at play there even when acknowledging your point about relative market size.
In this case, it's for the harmless charm of an imagined past, but the same forces are at play in some more dangerous forms of social conservatism.
But things can coexist. It's now easier to create music than ever, and there is more music created by more artists than ever. Most music is forgettable and just streamed as background music. But there is also room for superstars like Taylor Swift.
Things don't have to be either-or.