I, personally, would argue that market and industry conditions have changed so much to render pop music comparison between now and even a decade ago pretty much moot. The comparison is harder the further back you go. Superficial sugary crap purely to play to the masses is absolutely nothing new. There's a lot more of it, absolutely, but there's also just more music in general to choose from. A lot of niche genres now would have been niche one-band genres in the 70's. It's a tough thing to quantify, though. Yes Stairway to Heaven was on the pop charts but, well, there was nowhere else for it to go. Would it even chart now? Doubt it. Got nothing to do with the quality of the song but how the industry gets songs on the radio/TV these days.
One thing I do remember seeing was an experiment a few years back where several examples of songs with artistic merit scored by the experimenters were sampled from multiple eras. The same songs had their sonic quality changed via equalisation, volume boosting, degradation of bitrates, multiple file formats, etc. to give various good and bad quality recordings of the songs. The songs were played to people, the quality of the recording was the experimental manipulation here.
They found that, broadly speaking, songs which were considered pap scored highly with the best quality recordings but the crap quality meant the scores dropped off heaps. The 'good' songs, their scores weren't affected much at all. Being cautious, you could say the quality of the song does matter to people but what people get exposed to on a regular basis now is what's vastly different.
The country of exposure matters too. My band's album got some great reviews and airplay in The Netherlands, Belgium, Germany and Poland. In the US, we got some college radio play and a couple of quick mentions elsewhere (e.g. http://www.goldminemag.com/blogs/pro...new-label-home
), in OZ we got one review and absolutely zero interest from independent record companies so we had to sign to an American one just to get any distribution. It changes drastically too; every indie band with a glockenspiel/melodica gets killed to death on JJJ now whereas the same bands were playing to 5 people in the 90's. Conversely, every angsty garage band which would have dominated then is working their arses off to scrape together 20 people for a show now.
Can't help but feel a bit rejected....