Hip-hop was once a rebellious music that sampled songs without permission, was the subject of derision by politicians and became a target of law enforcement. But even as its teenage adherents got minivans and had kids, their love of hip-hop never left - and, with its fans’ maturation, came a new life for the originators of an art form that used to long for the mainstream legitimacy its progeny now enjoys.

But while new music by Nicki Minaj and Drake may rule the pop and urban charts, the hip-hop of a generation ago (like Salt-N-Pepa’s Push It, Young MC’s Bust A Move and others) is penetrating the most mainstream of venues, from classrooms to movie theaters to insurance commercials. And nowhere is “old school” hip-hop’s growth more evident than on your radio dial.

The New York Times reports that Houston station KROI tripled its audience when it switched to a classic hip-hop format. Indianapolis’ WRWM went from 15th most-listened to number 1 in just a month when it did the same. Rolling Stone reports that corporations like iHeartRadio (formerly Clear Channel) and others are now jumping to change flailing stations’ formats to hip-hop oldies as a result.

The emergence of classic hip-hop as a radio format is fantastic news for listeners who love the music - and it means a second chance for legacy artists and their families, many of whom saw little-to-no money in their heyday, to potentially reap royalties anew. Producers whose techniques shaped genres as divergent as pop, electronic dance music and soul, but who may have languished in obscurity, will finally get to be heard.

But as delightful as it is to hear the music of our youth back on the radio, the lack of diversity in the industry threatens to derail the resurgence of classic hip-hop and bury its history.

Even in the infancy of classic hip hop stations, corporate radio is looking to do to the genre what it did to classic rock. Turn on a rock oldies station and you’ll get hits by Led Zeppelin, the Eagles and the Beatles, with nary a nod to deeper album cuts, underground performers or the daring sounds that actually defined the era. Listen to KROI - the radio station that kicked off the classic hip-hop craze - or any of its copycats and there’s plenty of Snoop Dogg, Beastie Boys, Dr Dre and Notorious B.I.G., but barely a trace of the artists who impacted them and the genre, like Gang Starr, Rakim, Public Enemy and Boogie Down Productions.

The difference between those who get airplay on classic hip-hop stations, and those who don’t, could be about the lyrics and themes that made the genre rebellious in the first place. Some of the era’s defining moments, such as the 1991 beating of Rodney King, spread into songs of protest by a range of hip hop artists. Music by acts like Kam and Da Lench Mob (affiliates of rapper/actor Ice Cube) was explicitly confrontational toward white authority. Public Enemy’s Chuck D openly criticizes today’s urban radio, owned by the same companies that operate the classic hip-hop stations, for disrespecting black audiences by promoting negative imagery of women and people of color.

Beyond politics, corporate ownership and the pursuit of advertising may be most responsible for killing access to the full spectrum of hip-hop history. The Future of Music Coalition estimates that, since the passage of the Telecommunications Act of 1996, which allowed conglomerates to buy out dozens of independent black-owned stations, those stations increasingly focused on formulas over music. It’s produced, as Eric Weisbard remarks, a “top 40 democracy” where diversity suffers in the gilded cage of commercialism.

Tragically, media consolidation means not only does corporate radio control who gets played, but also which artists get recognition, who is perceived as a voice in a music’s history and who is erased from that history. All classic music formats suffer from that effect and it should be a concern to aficionados, students of music history and society at large, which risks losing our collective memories. In the case of hip-hop - as is the case with so much history in which young African-Americans are the protagonists - we also face the potential loss of the visionaries who helped make hip-hop music the global powerhouse it is today.

Commercial radio is benefiting handsomely from classic hip-hop. Listeners and artists must remind these outlets that they have an obligation to present the multiplicity of one of music’s most fearless genres, not just that which fits a white, corporate image of the genre. Hip-hop has fought hard for respect. In an era in which it is more commercially popular than ever before, hip-hop’s influencers, fans and advertisers must demand more of its radio gatekeepers for the past as well as for the future.