MTV was good for most of the 80s.
It started to go downhill when the M became "Michael Jackson" as in "MICHAEL JACKSON T V"
The album Thriller was released along with 3 videos you couldn't get away from. The "Billie Jean" video ( which is well done, very slick , and is also the MJ song I like best....nto counting the old JACKSON 5 stuff), the mini- movie, "Thriller" which was just too damn long for MTV and they played it too death ) I got really, really sick of seeing this 10 times a week!), and "Beat it" ( another slick production and an interesting video , but even better when Wierd Al spoofed it with "Eat It.") got real sick of seeing all three over and over and over.
Once Michael Jackson got center stage and then all the Rap and Hip Hop stuff started taking over , MTV was done as a music channel.
I think the early MTV was very slanted toward White groups like Devo, Pretenders, Talking Heads, Duran Duran, Psychedelic Furs, Kajagoogoo , and all those Post Punk bands....I believe the network got complaints from African American viewers that the station wasn't "Black" enough. Not only did they listen to the complaints they completely alienated White viewers by making thei programming "too Black."
I don't think they ever reached the proper mix. They went from being almost strictly for a young , middleclass, White audience to pandering to and audience that wanted Hip Hop , Rap and Pop and didn't care to watch Rock music videos. Then eventually to a network that showed NO music at all.