Just to use your example: YouTube is filled with talented writers and storytellers, who would have never been able to share their content in the past. *And* the traditional media complex is richer than ever.
I don’t think average quality matters. Just what you want to consume.
If anything, I’d be more open to the opposite argument. Media is so much richer and more engaging that it actually makes our lives worse. The quality of the drugs is too high!