it depends what you hear. if you hear dubstep or so you couldn't hear it in the 50s or 60s haha so nowaday is much better music^^
if you like rock maybe the past was better but that's the reason, they only had like rock/pop/country in the past nowadays you have an unbelieveable amount of genres so it makes sense you don't like as much percental than you did in the past but just because you don't like dubstep for example doesn't mean it's bad music.
the industry suffers a lot because of the "free" downloads so they only concentrate in the music they can still make money with. the industry shrank 50% in the last years because of the downloads. if you still search for music you like you will find it but you can't expect that the big labels have still so many good singers/bands. it's just to expensive to experment with music and to hope some people will buy it.
just search the indie market and you will find what you like.
and the same you say to this time people who loved classical music said in the 50s/60s... the beginning of the music groups and guysl like elvis almost killed the classical genre. not that there wasn't classical music after that but the people only had the beatles in their head lol