The music space is quite large, lots of musicians (various types, and there will be more and more genres created as time goes on). The more apparent ones are on the billboards, Shazam, charts, and for a lot of them to suit your taste, you'd have to dig around as mainstream music taste changes as audience changes. It doesn't mean people can't read music now a days (you have symphony, orchestra, guitarist prodigies popping up all the time, random Youtube talents, etc..), it just expresses what the mainstream at the time focuses on.
You got Youtube, and social media that has effect on what people frequently hear. Back then, it was the radio. I think people have a larger space to explore, but the lazy will get fed mainstream music.
Can we say an era's music is better over another? Music does get molded by the times (with the way media is consumed), and what gets highly marketed is decided by big companies, and what gets popularized is by audience reactions.