Actually it's been going on for centuries. Oswald Spengler's 'The Decline of The West' is the best book I have read on the subject and I would highly recommend it. 1916 was the year that the Victorian era really came crashing down. You could argue that was really the end of Western civilisation and that everything else since was its death throes.
The media in a free society is just a reflection of the society itself. For example, News of the World published trash because that's what they knew would sell. That's what people wanted. You can't blame the supplier entirely because he's only responding to the demand.