The easiest answer is the creation of Sugar Hill because it started off with basically the rap equivalent of a boy band.
But beyond that, it was clear that hip-hop was gonna see itself getting used by outsiders in the mid-80s... while it's becoming the sound of the youth, corporations wasted no time- Hollywood was making corny "rap movies", Fred Flintstone, the Pillsbury Doughboy, the Crash Test Dummies, Rodney Dangerfield, and who knows who else was rapping in commercials. Labels were already signing up rappers and turning them into more commercialized versions of themselves (particularly the Fat Boys)... these were all things destined to eventually go too far later down the line.