The thing about the advent of MTV is, good or bad, in some cases, the look became bigger than the actual music.
Don't get me wrong, there was a lot of great music that was put out in the 80s, as with any generation. It progressed and evolved from drums and guitar music into a more sparse and electric, synthetic sound.
But, that's nothing new. Music has always embraced and experimented with the technology of the times.
There have always been music videos, too, but MTV embraced that aspect, focused on it and made it the centerpiece of the song.
And, let's face facts here, there were bands that put far more emphasis on their videos than their music. Hair metal jumps right to mind. VO-5, mascara, scarves, lipstick and rouge all took center stage, while 95% of the songs were formulaic, about partying and having a good time. Other than a couple of pretty good guitarists, that genre didn't contribute much to the evolution of music.