The standards for "quality music" have declined. The songs that we are listening to today is definitely quite different then we used to have. There seems to be very little thought behind the songs anymore with the same lyrics being repeated over and over. I know it makes money but come on.
There are more and more rapper, hip-hop, and pop artist that make music that is just a repetitive chorus. Nas (an old school rapper) fairly recently made a song called, Shuck and Jive about the decline in music in the last few years. This decline is subject of attention for a lot of school old artist.
Yes, the standards for quality music have declined, because today, anyone can produce music. Today, it is so easy for anyone to set up a recorder and digitally record to their computer and then sell it on iTunes. With there being no quality filters up front, the quality of music declines quickly.
I believe the overall standards for quality music has declined, but the music industry has also taken a financial blow with people sharing the music across the Internet. This has led to less investment in music because there is less profit. I think it has more to do with this problem than anything else.
While some people may not like the type of music that is now on the charts, it is still quality music and it is all a matter of opinion. Every era there will be people who dont like the type of music that is in the charts at that time as it isnt what they grew up with or isnt their taste of music but that doesnt make it any lower of a standard.