Some artists contain universes. In 1984 hip hop was kinda silly break dance music then it wasn't.
Well it did start as party music. But to discredit party music as mindless is too hurtful to the genre. Basically, Hip-Hop's instrumental origins come from DJs taking the "break" or the instrumental rhythm part, and repeating them, crossfading them with other song's breaks, and adding turntable tricks along the way. The lyrics in this case came from the DJ announcing moves to the breakdancers. This had a lot of importance because breakdancing was seen as a way of expressing and getting rid of aggression, rather than through violent means. These blockparties were an important part of the culture and of breaking down tension. This was eventually mixed with Hip-Hop's vocal influence: poets like Gil-Scott Heron and America's take on the Jamaican art of "toasting" as popularized by Bootsy Collins and Bob Dylan. When these two forms combined, that's when the New School Of Hip-Hop really formed, where artists like Run-DMC and LL Cool J took both aspects and combined them into a completely new sound. If you haven't seen it, I'd recommend the doc Rhyme & Reason. It's on Netflix, and follows Hip-Hop from its inception in 1975 up until 1997 when the doc was made. They interview a bunch of legends like Ice-T, KRS-One, Pharcyde, Run-DMC, Dr. Dre, Heavy D, Notorious BIG, Ice Cube, Ras Kass, Q-Tip, Arrested Development, Da Brat, Salt & Pepa, Wu-Tang, Redman, and so many more.
The Message wouldn't have been written if Gill Scott or The Last Poets hadn't plowed the field ahead of time. "The New Sound" had a lot of socially conscious stuff that came before it. Afrika Bambaataa, Kurtis Blow and The Furious Five are all good examples. And surly the whole political consciousness stuff didn't hit it's full blossom until, I'd say, Public Enemy hit the the scene but it was foundational right from the start.
Oh don't get me wrong, I know it was there from the beginning, but it was still largely a "party" scene. Afrika Bambaataa's politically conscious songs were still very party-oriented, and Grandmaster Flash actually wasn't comfortable with The Message being on the album because he considered it too different from the style. The synthesis was definitely there from the beginning, but it really gained prevelance in the early 80's when there was more importance put upon the lyricism. This is part of why I always considered Hip-Hop and Punk to be sibling genres. They didn't arise out of political reasons, but they gravitated to them so easily.