There's always been a lot of terrible pop music. Even when I was 11 or 12 I knew Paper Lace and Chicory Tip were pants. I watched a 1984 episode of Top of The Pops last night, and it was pretty bad ('Breakdance Party', anyone?) with a couple of decent tunes from Marillion and Ultravox (toe curling videos for both mind you).
I do wonder where the good pop songwriters are now though - Ed Sheeran and his contemporaries can't hold a candle to Elvis Costello, Nick Lowe, Chrissie Hynde or Difford & Tilbrook. There also seems to be a marked lack of any kind of sense of humour or 'fun' in the pop that I hear now, it all seems to be angsty imaginary relationship problems.
Likewise, no-one appears to be interested in writing anything political; I can't imagine a song like 'Shipbuilding' or 'London Calling' getting airplay nowadays.