When rap came out 30 years ago I thought it was just a fad


Now it seems like it dominates the music industry, movies and fashion. My only question is why?

taters
I couldn't agree with you more taters. I myself am one who finds Rap not merely unlistenable, but unbearable. When heard, I do everything in my power to get as far away from the sound source as possible. I not only can't answer why it has stayed popular as long as it had, I can't fathom how it can be liked in the first place. But I am about as far from Rap's target audience as you can get. You too taters, apparently!
Rap caters to the lowest common denominator. Just like the Jerry Springer show and the Kardashians. And I despise all 3.
I have no doubt that Rap is viewed in certain circles as merely the current phase in the continuing downward spiral of Western Civilization, the dumbing down of humanity. Rock n' Roll was certainly viewed thusly in the mid-50's by the WWII generation, and I've read that intellectuals in the 20's felt the same way about early Jazz. I'm thinking every generation views the following one in that way. And it may be true---no music that followed J.S. Bach is as good as his ;-)! 
I take a much simpler view on this.  Rap occupies the same place with our culture today, that rock did 45 years ago (I am 58 now).  As I think to myself when I see most of what is around today (be it clothes, fashion, music, etc.) ... we had our time at the plate, now it is time to step left.

Rap will pass as the sound of the masses 20 years or so from now, just like rock has past for the most part.  Many baby boomers just have a hard time accepting that rap is as big as rock was.  

My mom passed away 3 years ago at age 90.  During her last year, I spent most every day either with her in the nursing home section of the hospital or in the hospice we set up in her apartment.  When the patients had lunch in the lunchroom, the staff piped in big band music from the 40's.  It will be no different for us ... just not sure how I will feel about the Stones in 2046 ... hope they don't play any Bon Jovi.

Happy New Year!  Grease for Peace!

Rich 
I think it's the sworn duty of every generation to annoy the generation that came before them.

I'm 58. My parents couldn't stand "my" music when I was growing up (Ten Years After, Deep Purple, Santana, The Who, Allman Bros, et al.) I loathed my father's classical, big band, and chamber music, although I've come around a bit since.

I view rap/hip-hop the same way we've all felt about "our" music; as the voice of the current generation. Were we not rebelling against current convention by turning it up loud, growing our hair long, and dressing shabby? Today's hip-hop is the current generation's street music, blooming from the frustration and anger they feel due to their conditions. (I suppose. I'm no expert on this.) For many of them, music is a way up and out, an opportunity to be seen and, possibly, to make a fortune.

I don't get hip-hop. I don't appreciate it at all. I think it's all crap. But I understand where it comes from. Now, if it would just go away. Not likely, though.