Tl:dr Up the Irons \m/
I agree that if you on listening to the radio or focusing on what is popular, then yes music is generic, unoriginal, and catchy. There are and groups out there that don't fit this profile, but they typically would not be played on any radio station.
Best Music/genre/artist/era
Myself I would vote for 70's/80's rock and metal. You have Led Zeppelin, Black Sabbath, Iron Maiden, Slayer, Metallica, Pink Floyd.
Best overall (obviously an opinion) would be Iron Maiden. To this day they have never really had "Hit song" They do have songs that are more recognizable.....the two or three that get played on the radio once in a blue moon. Their success has purely been driven by their fan base around the world. They pull crowds of 40,000 all over central and south america, and over 100,000 in Brazil. As well as playing the European concert circuits, Japan, India, Dubai. They are still touring and pulling these crowds to this day. They are truly a global power. Not to mention their lead singer was an olympic level fencer, commercial airline pilot purely because he liked flying, and all around bad ass.
For a little taste, one of my favs.
Wasted Years